Compositions and methods comprising sequences having meganuclease activity

Abstract

Compositions and methods comprising polynucleotides and polypeptides having meganuclease activity are provided. Further provided are nucleic acid constructs, yeast, plants, plant cells, explants, seeds and grain having the meganuclease sequences. Various methods of employing the meganuclease sequences are provided. Such methods include, for example, methods for producing a meganuclease with increased activity at a wide range of temperatures, methods for producing a yeast, plant, plant cell, explant or seed comprising a meganuclease with increased activity.

1 . An isolated or recombinant polynucleotide comprising a nucleotide sequence encoding a meganuclease polypeptide, said polypeptide comprising:
 a) an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:1 selected from the group consisting of positions 2, 12, 16, 22, 23, 31, 36, 43, 50, 56, 58, 59, 62, 71, 72, 73, 80, 81, 82, 86, 91, 95, 98, 103, 113, 114, 116, 117, 118, 121, 124, 128, 129, 131, 147, 151, 153, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 194, 195, 196, 197, 200, 203, 204, 209, 222, 232, 236, 237, 246, 254, 258, 267, 278, 281, 282, 289, 308, 311, 312, 316, 318, 319, 334, 339, 340, 342, 345, 346, 348 and combinations thereof; or,   b) an amino acid sequence having at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43 or 44 of any of the amino acid modification of (a).   
     
     
         2 - 28 . (canceled) 
     
     
         29 . An isolated polypeptide having meganuclease activity, said polypeptide comprising:
 a) an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:1 selected from the group consisting of positions 2, 12, 16, 22, 23, 31, 36, 43, 50, 56, 58, 59, 62, 71, 72, 73, 80, 81, 82, 86, 91, 95, 98, 103, 113, 114, 116, 117, 118, 121, 124, 128, 129, 131, 147, 151, 153, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 194, 195, 196, 197, 200, 203, 204, 209, 222, 232, 236, 237, 246, 254, 258, 267, 278, 281, 282, 289, 308, 311, 312, 316, 318, 319, 334, 339, 340, 342, 345, 346, 348 and combinations thereof; or,   b) an amino acid sequence having at least 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43 or 44 of any of the amino acid modification of (a);   
     
     
         30 . The isolated polypeptide of  claim 29 , wherein said polypeptide has at least 80% sequence identity to SEQ ID NO: 1. 
     
     
         31 . The isolated polypeptide of  claim 29 , wherein said at least one amino acid modification comprises:
 a) an aspartic acid (D) at a position corresponding to amino acid position 2 in SEQ ID NO: 1;   b) a histidine (H) at a position corresponding to amino acid position 12 in SEQ ID NO: 1;   c) an isoleucine (I) at a position corresponding to amino acid position 16 in SEQ ID NO: 1;   d) a cysteine (C) at a position corresponding to amino acid position 22 in SEQ ID NO: 1;   e) a leucine (L) at a position corresponding to amino acid position 23 in SEQ ID NO: 1;   f) an arginine (R) at a position corresponding to amino acid position 31 in SEQ ID NO: 1;   g) an asparagine (N) at a position corresponding to amino acid position 36 in SEQ ID NO: 1;   h) a leucine (L) at a position corresponding to amino acid position 43 in SEQ ID NO: 1;   i) an arginine (R) or lysine (K) at a position corresponding to amino acid position 50 in SEQ ID NO: 1;   j) a leucine (L) at a position corresponding to amino acid position 56 in SEQ ID NO: 1;   k) an isoleucine (I) at a position corresponding to amino acid position 58 in SEQ ID NO: 1;   l) a histidine (H) or alanine (A) at a position corresponding to amino acid position 59 in SEQ ID NO: 1;   m) a valine (V) at a position corresponding to amino acid position 62 in SEQ ID NO: 1;   n) a lysine (K) at a position corresponding to amino acid position 71 in SEQ ID NO: 1;   o) a threonine (T) at a position corresponding to amino acid position 72 in SEQ ID NO: 1;   p) an alanine (A) at a position corresponding to amino acid position 73 in SEQ ID NO: 1;   q) an arginine (R) at a position corresponding to amino acid position 80 in SEQ ID NO: 1;   r) a lysine (K) at a position corresponding to amino acid position 81 in SEQ ID NO: 1;   s) an arginine (R) at a position corresponding to amino acid position 82 in SEQ ID NO: 1;   t) an aspartic acid (D) at a position corresponding to amino acid position 86 in SEQ ID NO: 1;   u) an isoleucine (I) at a position corresponding to amino acid position 91 in SEQ ID NO: 1;   v) an isoleucine (I) at a position corresponding to amino acid position 95 in SEQ ID NO: 1;   w) an arginine (R) at a position corresponding to amino acid position 98 in SEQ ID NO: 1;   x) a valine (V) at a position corresponding to amino acid position 103 in SEQ ID NO: 1;   y) a serine (S) at a position corresponding to amino acid position 113 in SEQ ID NO: 1;   z) a proline (P) at a position corresponding to amino acid position 114 in SEQ ID NO: 1;   aa) an arginine (R) at a position corresponding to amino acid position 116 in SEQ ID NO: 1;   bb) a glycine (G) at a position corresponding to amino acid position 117 in SEQ ID NO: 1;   cc) a threonine (T) at a position corresponding to amino acid position 118 in SEQ ID NO: 1;   dd) a an glycine (G) at a position corresponding to amino acid position 121 in SEQ ID NO: 1;   ee) an arginine (R) at a position corresponding to amino acid position 124 in SEQ ID NO: 1;   if) a cysteine (C) at a position corresponding to amino acid position 128 in SEQ ID NO: 1;   gg) an alanine (A) at a position corresponding to amino acid position 129 in SEQ ID NO: 1;   hh) an arginine (R) at a position corresponding to amino acid position 131 in SEQ ID NO: 1;   ii) a serine (S) at a position corresponding to amino acid position 147 in SEQ ID NO: 1;   jj) an alanine (A) at a position corresponding to amino acid position 151 in SEQ ID NO: 1;   kk) a leucine (L) or a methionine (M) at a position corresponding to amino acid position 153 in SEQ ID NO: 1;   ll) a tryptophan (W) at a position corresponding to amino acid position 159 in SEQ ID NO: 1;   mm) a glutamic acid (E) at a position corresponding to amino acid position 160 in SEQ ID NO: 1;   nn) a valine (V) at a position corresponding to amino acid position 161 in SEQ ID NO: 1;   oo) a tyrosine (Y) at a position corresponding to amino acid position 162 in SEQ ID NO: 1;   pp) an arginine (R) at a position corresponding to amino acid position 163 in SEQ ID NO: 1;   qq) a histidine (H) at a position corresponding to amino acid position 164 in SEQ ID NO: 1;   rr) a leucine (L) at a position corresponding to amino acid position 165 in SEQ ID NO: 1;   ss) an arginine (R) at a position corresponding to amino acid position 166 in SEQ ID NO: 1;   tt) a histidine (H) at a position corresponding to amino acid position 167 in SEQ ID NO: 1;   uu) a proline (P) at a position corresponding to amino acid position 168 in SEQ ID NO: 1;   vv) an alanine (A) at a position corresponding to amino acid position 169 in SEQ ID NO: 1;   ww) a proline (P) at a position corresponding to amino acid position 170 in SEQ ID NO: 1;   xx) a histidine (H) at a position corresponding to amino acid position 171 in SEQ ID NO: 1;   yy) a proline (P) at a position corresponding to amino acid position 172 in SEQ ID NO: 1;   zz) an arginine (R) at a position corresponding to amino acid position 173 in SEQ ID NO: 1;   aaa) a leucine (L) at a position corresponding to amino acid position 174 in SEQ ID NO: 1;   bbb) a proline (P) at a position corresponding to amino acid position 175 in SEQ ID NO: 1;   ccc) a glutamine (Q) at a position corresponding to amino acid position 176 in SEQ ID NO: 1;   ddd) an alanine (A) at a position corresponding to amino acid position 177 in SEQ ID NO: 1;   eee) an arginine (R) at a position corresponding to amino acid position 178 in SEQ ID NO: 1;   fff) a valine (V) at a position corresponding to amino acid position 179 in SEQ ID NO: 1;   ggg) a glutamine (Q) at a position corresponding to amino acid position 180 in SEQ ID NO: 1;   hhh) a valine (V) at a position corresponding to amino acid position 182 in SEQ ID NO: 1;   iii) a proline (P) at a position corresponding to amino acid position 183 in SEQ ID NO: 1;   jjj) a lysine (K) at a position corresponding to amino acid position 184 in SEQ ID NO: 1;   kkk) a threonine (T) or a histidine (H) at a position corresponding to amino acid position 185 in SEQ ID NO: 1;   lll) a serine (S) at a position corresponding to amino acid position 186 in SEQ ID NO: 1;   mmm) a glutamic acid (E) at a position corresponding to amino acid position 187 in SEQ ID NO: 1;   nnn) a leucine (L) at a position corresponding to amino acid position 188 in SEQ ID NO: 1;   ooo) a glutamic acid (E) at a position corresponding to amino acid position 189 in SEQ ID NO: 1;   ppp) a glutamine (Q) at a position corresponding to amino acid position 190 in SEQ ID NO: 1;   qqq) a leucine (L) at a position corresponding to amino acid position 191 in SEQ ID NO: 1;   rrr) a proline (P) at a position corresponding to amino acid position 194 in SEQ ID NO: 1;   sss) a lysine (K) at a position corresponding to amino acid position 195 in SEQ ID NO: 1;   ttt) a serine (S) at a position corresponding to amino acid position 196 in SEQ ID NO: 1;   uuu) a phenylalanine (F) at a position corresponding to amino acid position 197 in SEQ ID NO: 1;   vvv) an isoleucine (I) at a position corresponding to amino acid position 200 in SEQ ID NO: 1;   www) a valine (V) at a position corresponding to amino acid position 203 in SEQ ID NO: 1;   xxx) a leucine (L) at a position corresponding to amino acid position 204 in SEQ ID NO: 1;   yyy) a cysteine (C) at a position corresponding to amino acid position 209 in SEQ ID NO: 1;   zzz) a leucine (L) at a position corresponding to amino acid position 222 in SEQ ID NO: 1;   aaaa) an isoleucine (I) at a position corresponding to amino acid position 232 in SEQ ID NO: 1;   bbbb) a serine (S) at a position corresponding to amino acid position 236 in SEQ ID NO: 1;   cccc) a leucine (L) or an arginine (R) at a position corresponding to amino acid position 237 in SEQ ID NO: 1;   dddd) a histidine (H) at a position corresponding to amino acid position 246 in SEQ ID NO: 1;   eeee) an isoleucine (I) at a position corresponding to amino acid position 254 in SEQ ID NO: 1;   ffff) a serine (S) at a position corresponding to amino acid position 258 in SEQ ID NO: 1;   gggg) an arginine (R) at a position corresponding to amino acid position 267 in SEQ ID NO: 1;   hhhh) an isoleucine (I) at a position corresponding to amino acid position 278 in SEQ ID NO: 1;   iiii) a tyrosine (Y) at a position corresponding to amino acid position 281 in SEQ ID NO: 1;   jjjj) a phenylalanine (F) at a position corresponding to amino acid position 282 in SEQ ID NO: 1;   kkkk) a threonine (T) at a position corresponding to amino acid position 289 in SEQ ID NO: 1;   llll) a glycine (G) at a position corresponding to amino acid position 308 in SEQ ID NO: 1;   mmmm) an arginine (R) at a position corresponding to amino acid position 311 in SEQ ID NO: 1;   nnnn) an alanine (A) at a position corresponding to amino acid position 312 in SEQ ID NO: 1;   oooo) an alanine (A) at a position corresponding to amino acid position 316 in SEQ ID NO: 1;   pppp) an arginine (R) at a position corresponding to amino acid position 318 in SEQ ID NO: 1   qqqq) an alanine (A) at a position corresponding to amino acid position 334 in SEQ ID NO: 1;   rrrr) a phenylalanine (F) at a position corresponding to amino acid position 339 in SEQ ID NO: 1;   ssss) a glycine (G) or a leucine (L) at a position corresponding to amino acid position 340 in SEQ ID NO: 1;   tttt) a serine (S) at a position corresponding to amino acid position 342 in SEQ ID NO: 1;   uuuu) an asparagine (N) at a position corresponding to amino acid position 345 in SEQ ID NO: 1;   vvvv) an asparagine (N) at a position corresponding to amino acid position 346 in SEQ ID NO: 1;   wwww) an asparagine (N) at a position corresponding to amino acid position 348 in SEQ ID NO: 1; or,   xxxx) any combination of a) to wwww).   
     
     
         32 . The isolated polypeptide of  claim 29 , wherein said polypeptide further comprises:
 a) an aspartic acid (D) at a position corresponding to amino acid position 2 in SEQ ID NO: 1;   b) a histidine (H) at a position corresponding to amino acid position 12 in SEQ ID NO: 1;   c) an isoleucine (I) at a position corresponding to amino acid position 16 in SEQ ID NO: 1;   d) a serine (S) or an alanine (A) at a position corresponding to amino acid position 19 in SEQ ID NO: 1;   e) a cysteine (C) at a position corresponding to amino acid position 22 in SEQ ID NO: 1;   f) a leucine (L) at a position corresponding to amino acid position 23 in SEQ ID NO: 1;   g) a methionine (M) at a position corresponding to amino acid position 24 in SEQ ID NO: 1;   h) an arginine (R) or an alanine (A) at a position corresponding to amino acid position 28 in SEQ ID NO: 1;   i) an arginine (R), alanine (A), glutamine (Q), cysteine (C), glycine (G), serine (S), threonine (T), leucine (L), glutamic acid (E), or a proline (P) at a position corresponding to amino acid position 30 in SEQ ID NO: 1;   j) an arginine (R) at a position corresponding to amino acid position 31 in SEQ ID NO: 1;   k) an arginine (R), alanine (A), lysine (K) glutamine (Q), glycine (G) or a leucine (L) at a position corresponding to amino acid position 32 in SEQ ID NO: 1;   l) an asparagine (N) at a position corresponding to amino acid position 36 in SEQ ID NO: 1;   m) a leucine (L) at a position corresponding to amino acid position 43 in SEQ ID NO: 1;   n) an arginine (R) or lysine (K) at a position corresponding to amino acid position 50 in SEQ ID NO: 1;   o) an isoleucine (I) or a leucine (L) at a position corresponding to amino acid position 54 in SEQ ID NO: 1;   p) a leucine (L) at a position corresponding to amino acid position 56 in SEQ ID NO: 1;   q) a glutamic acid (E) at a position corresponding to amino acid position 57 in SEQ ID NO: 1;   r) an isoleucine (I) at a position corresponding to amino acid position 58 in SEQ ID NO: 1;   s) a histidine (H) or alanine (A) at a position corresponding to amino acid position 59 in SEQ ID NO: 1;   t) a valine (V) at a position corresponding to amino acid position 62 in SEQ ID NO: 1;   u) a lysine (K) at a position corresponding to amino acid position 71 in SEQ ID NO: 1;   v) a threonine (T) at a position corresponding to amino acid position 72 in SEQ ID NO: 1;   w) an alanine (A) at a position corresponding to amino acid position 73 in SEQ ID NO: 1;   x) a glycine (G) at a position corresponding to amino acid position 79 in SEQ ID NO: 1;   y) an arginine (R) at a position corresponding to amino acid position 80 in SEQ ID NO: 1;   z) a lysine (K) at a position corresponding to amino acid position 81 in SEQ ID NO: 1;   aa) an arginine (R) at a position corresponding to amino acid position 82 in SEQ ID NO: 1;   bb) an aspartic acid (D) at a position corresponding to amino acid position 86 in SEQ ID NO: 1;   cc) a leucine (L) at a position corresponding to amino acid position 87 in SEQ ID NO: 1;   dd) an isoleucine (I) at a position corresponding to amino acid position 91 in SEQ ID NO: 1;   ee) an isoleucine (I) at a position corresponding to amino acid position 95 in SEQ ID NO: 1;   ff) an arginine (R) at a position corresponding to amino acid position 98 in SEQ ID NO: 1;   gg) a valine (V) at a position corresponding to amino acid position 103 in SEQ ID NO: 1;   hh) an alanine (A) at a position corresponding to amino acid position 105 in SEQ ID NO: 1;   ii) an arginine (R) at a position corresponding to amino acid position 111 in SEQ ID NO: 1;   jj) a serine (S) at a position corresponding to amino acid position 113 in SEQ ID NO: 1;   kk) a proline (P) at a position corresponding to amino acid position 114 in SEQ ID NO: 1;   ll) an arginine (R) at a position corresponding to amino acid position 116 in SEQ ID NO: 1;   mm) a an glycine (G) at a position corresponding to amino acid position 117 in SEQ ID NO: 1;   nn) a threonine (T) at a position corresponding to amino acid position 118 in SEQ ID NO: 1;   oo) a an glycine (G) at a position corresponding to amino acid position 121 in SEQ ID NO: 1;   pp) an arginine (R) at a position corresponding to amino acid position 124 in SEQ ID NO: 1;   qq) a cysteine (C) at a position corresponding to amino acid position 128 in SEQ ID NO: 1;   rr) an alanine (A) at a position corresponding to amino acid position 129 in SEQ ID NO: 1;   ss) an arginine (R) at a position corresponding to amino acid position 131 in SEQ ID NO: 1;   tt) a valine (V) at a position corresponding to amino acid position 132 in SEQ ID NO: 1;   uu) a serine (S) at a position corresponding to amino acid position 147 in SEQ ID NO: 1;   vv) an alanine (A) at a position corresponding to amino acid position 151 in SEQ ID NO: 1;   ww) a leucine (L) or a methionine (M) at a position corresponding to amino acid position 153 in SEQ ID NO: 1;   xx) a tryptophan (W) at a position corresponding to amino acid position 159 in SEQ ID NO: 1;   yy) a glutamic acid (E) at a position corresponding to amino acid position 160 in SEQ ID NO: 1;   zz) a valine (V) at a position corresponding to amino acid position 161 in SEQ ID NO: 1;   aaa) a tyrosine (Y) at a position corresponding to amino acid position 162 in SEQ ID NO: 1;   bbb) an arginine (R) at a position corresponding to amino acid position 163 in SEQ ID NO: 1;   ccc) a histidine (H) at a position corresponding to amino acid position 164 in SEQ ID NO: 1;   ddd) a leucine (L) at a position corresponding to amino acid position 165 in SEQ ID NO: 1;   eee) an arginine (R) at a position corresponding to amino acid position 166 in SEQ ID NO: 1;   fff) a histidine (H) at a position corresponding to amino acid position 167 in SEQ ID NO: 1;   ggg) a proline (P) at a position corresponding to amino acid position 168 in SEQ ID NO: 1;   hhh) an alanine (A) at a position corresponding to amino acid position 169 in SEQ ID NO: 1;   iii) a proline (P) at a position corresponding to amino acid position 170 in SEQ ID NO: 1;   jjj) a histidine (H) at a position corresponding to amino acid position 171 in SEQ ID NO: 1;   kkk) a proline (P) at a position corresponding to amino acid position 172 in SEQ ID NO: 1;   lll) an arginine (R) at a position corresponding to amino acid position 173 in SEQ ID NO: 1;   mmm) a leucine (L) at a position corresponding to amino acid position 174 in SEQ ID NO: 1;   nnn) a proline (P) at a position corresponding to amino acid position 175 in SEQ ID NO: 1;   000) a glutamine (Q) at a position corresponding to amino acid position 176 in SEQ ID NO: 1;   ppp) an alanine (A) at a position corresponding to amino acid position 177 in SEQ ID NO: 1;   qqq) an arginine (R) at a position corresponding to amino acid position 178 in SEQ ID NO: 1;   rrr) a valine (V) at a position corresponding to amino acid position 179 in SEQ ID NO: 1;   sss) a glutamine (Q) at a position corresponding to amino acid position 180 in SEQ ID NO: 1;   ttt) a valine (V) at a position corresponding to amino acid position 182 in SEQ ID NO: 1;   uuu) a proline (P) at a position corresponding to amino acid position 183 in SEQ ID NO: 1;   vvv) a lysine (K) at a position corresponding to amino acid position 184 in SEQ ID NO: 1;   www) a threonine (T) or a histidine (H) at a position corresponding to amino acid position 185 in SEQ ID NO: 1;   xxx) a serine (S) at a position corresponding to amino acid position 186 in SEQ ID NO: 1;   yyy) a glutamic acid (E) at a position corresponding to amino acid position 187 in SEQ ID NO: 1;   zzz) a leucine (L) at a position corresponding to amino acid position 188 in SEQ ID NO: 1;   aaaa) a glutamic acid (E) at a position corresponding to amino acid position 189 in SEQ ID NO: 1;   bbbb) a glutamine (Q) at a position corresponding to amino acid position 190 in SEQ ID NO: 1;   cccc) a leucine (L) at a position corresponding to amino acid position 191 in SEQ ID NO: 1;   dddd) an amino acid deletion at a position corresponding to amino acid position 192 in SEQ ID NO: 1;   eeee) a proline (P) at a position corresponding to amino acid position 194 in SEQ ID NO: 1;   ffff) a lysine (K) at a position corresponding to amino acid position 195 in SEQ ID NO: 1;   gggg) a serine (S) at a position corresponding to amino acid position 196 in SEQ ID NO: 1;   hhhh) a phenylalanine (F) at a position corresponding to amino acid position 197 in SEQ ID NO: 1;   iiii) an isoleucine (I) at a position corresponding to amino acid position 200 in SEQ ID NO: 1;   jjjj) a valine (V) at a position corresponding to amino acid position 203 in SEQ ID NO: 1;   kkkk) a leucine (L) at a position corresponding to amino acid position 204 in SEQ ID NO: 1;   llll) an alanine (A) or a serine (S) at a position corresponding to amino acid position 206 in SEQ ID NO: 1;   mmmm) a cysteine (C) at a position corresponding to amino acid position 209 in SEQ ID NO: 1;   nnnn) a leucine (L) at a position corresponding to amino acid position 222 in SEQ ID NO: 1;   oooo) a methionine (M) at a position corresponding to amino acid position 211 in SEQ ID NO: 1;   pppp) an isoleucine (I) at a position corresponding to amino acid position 232 in SEQ ID NO: 1;   qqqq) a serine (S) at a position corresponding to amino acid position 236 in SEQ ID NO: 1;   rrrr) a leucine (L) or an arginine (R) at a position corresponding to amino acid position 237 in SEQ ID NO: 1;   ssss) an isoleucine (I) or a leucine (L) at a position corresponding to amino acid position 241 in SEQ ID NO: 1;   tttt) a glutamic acid (E) at a position corresponding to amino acid position 244 in SEQ ID NO: 1;   uuuu) a histidine (H) at a position corresponding to amino acid position 246 in SEQ ID NO: 1;   vvvv) an aspartic acid (D) or histidine (H) at a position corresponding to amino acid position 253 in SEQ ID NO: 1;   wwww) an isoleucine (I) at a position corresponding to amino acid position 254 in SEQ ID NO: 1;   xxxx) a serine (S) at a position corresponding to amino acid position 258 in SEQ ID NO: 1;   yyyy) an arginine (R) at a position corresponding to amino acid position 267 in SEQ ID NO: 1;   zzzz) an isoleucine (I) at a position corresponding to amino acid position 278 in SEQ ID NO: 1;   aaaaa) a tyrosine (Y) at a position corresponding to amino acid position 281 in SEQ ID NO: 1;   bbbbb) a phenylalanine (F) at a position corresponding to amino acid position 282 in SEQ ID NO: 1;   ccccc) a threonine (T) at a position corresponding to amino acid position 289 in SEQ ID NO: 1;   ddddd) an alanine (A) at a position corresponding to amino acid position 292 in SEQ ID NO: 1;   eeeee) a glycine (G) at a position corresponding to amino acid position 308 in SEQ ID NO: 1;   fffff) an arginine (R) at a position corresponding to amino acid position 311 in SEQ ID NO: 1;   ggggg) an alanine (A) at a position corresponding to amino acid position 312 in SEQ ID NO: 1;   hhhhh) an alanine (A) at a position corresponding to amino acid position 316 in SEQ ID NO: 1;   iiiii) an arginine (R) at a position corresponding to amino acid position 318 in SEQ ID NO: 1   jjjjj) a valine (V) at a position corresponding to amino acid position 319 in SEQ ID NO: 1;   kkkkk) an alanine (A) at a position corresponding to amino acid position 334 in SEQ ID NO: 1;   lllll) a phenylalanine (F) at a position corresponding to amino acid position 339 in SEQ ID NO: 1;   mmmmm) a glycine (G) or a leucine (L) at a position corresponding to amino acid position 340 in SEQ ID NO: 1;   nnnnn) a serine (S) at a position corresponding to amino acid position 342 in SEQ ID NO: 1;   ooooo) an asparagine (N) at a position corresponding to amino acid position 345 in SEQ ID NO: 1;   ppppp) an asparagine (N) at a position corresponding to amino acid position 346 in SEQ ID NO: 1; or,   qqqqq) an asparagine (N) at a position corresponding to amino acid position 348 in SEQ ID NO: 1; or,   rrrrr) any combination of a) to qqqqq).   
     
     
         33 . The isolated polypeptide of  claim 29  selected from the group consisting of SEQ ID NOs: 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 251, 252, 253, 272, 273, 274, 275, 272, 273, 274, 275, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402, 430, 431, 432 and 433. 
     
     
         34 . The isolated polypeptide of  claim 29 , wherein the polypeptide is capable of recognizing and cleaving a meganuclease recognition sites selected from the group consisting of SEQ ID NO: 2, SEQ ID NO: 85, SEQ ID NO: 269, SEQ ID NO:281, SEQ ID NO: 331, SEQ ID NO:358, SEQ ID NO:390, SEQ ID NO:423 or SEQ ID NO:424. 
     
     
         35 . The isolated polypeptide of  claim 29 , wherein said polypeptide has an increased meganuclease activity when compared to a control meganuclease that lacks said amino acid modification. 
     
     
         36 . The isolated polypeptide of  claim 29 , wherein said control meganuclease is selected from the group of SEQ ID NO:1, SEQ ID NO: 86, SEQ ID NO: 250, SEQ ID NO:270, SEQ ID NO:271, SEQ ID NO:282, SEQ ID NO:283, SEQ ID NO: 329, SEQ ID NO:356, SEQ ID NO:389, SEQ ID NO:429 or SEQ ID NO:435. 
     
     
         37 . The isolated polypeptide of  claim 29 , wherein the increased meganuclease activity is evidenced by:
 a. a higher yeast assay score when compared to the control meganuclease that lacks said amino acid modification; or,   b. a higher target site mutation rate when compared to the control meganuclease that lacks said amino acid modification; or,   c. a higher in-vitro cutting when compared to the control meganuclease that lacks said amino acid modification; or,   d. any combination of (a), (b) and (c).   
     
     
         38 . A composition comprising at least one or more polypeptides of  claim 29 . 
     
     
         39 - 44 . (canceled) 
     
     
         45 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, said polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:1 selected from the group consisting of positions 16, 22, 50, 56, 59, 71, 81, 103, 121, 153, 185, 209, 222, 246, 258, 281, 308, 316, 345, 346, and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO: 2. 
     
     
         46 - 52 . (canceled) 
     
     
         53 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, the polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:270 selected from the group consisting of positions 16, 22, 50, 71, 185, 246, 258, 316 and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO: 269. 
     
     
         54 . (canceled) 
     
     
         55 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, the polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:282 selected from the group consisting of positions 12, 16, 22, 31, 50, 56, 59, 62, 81, 98, 103, 105, 116, 118, 121, 153, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 258, 281, 308, 312, 316, 319, and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO:281. 
     
     
         56 - 58 . (canceled) 
     
     
         59 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, the polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:329 selected from the group consisting of positions 12, 32, 50, 56, 80, 105, 124, 129, 131, 153, 185, 311, 316, 318, 340, and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO: 328. 
     
     
         60 - 62 . (canceled) 
     
     
         63 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, the polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:356 selected from the group consisting of positions 12, 24, 36, 50, 56, 62, 73, 80, 124, 129, 147, 182, 203, 237, 252, 311, 316, 318, 340, 348, and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO: 355. 
     
     
         64 - 66 . (canceled) 
     
     
         67 . An isolated or recombinant polynucleotide encoding a meganuclease polypeptide, the polypeptide comprising an amino acid sequence having at least one amino acid modification at an amino acid position corresponding to a position of SEQ ID NO:389 selected from the group consisting of positions 12, 50, 56, 124, 129, 131, 153, 211, 237, 311, 316, and position 318, and combinations thereof, and wherein the polypeptide is capable of recognizing and cleaving a meganuclease target site comprising SEQ ID NO: 388. 
     
     
         68 - 71 . (canceled) 
     
     
         72 . A yeast, plant, plant cell, explant or seed comprising the recombinant polynucleotide of  claim 45 . 
     
     
         73 . A method of introducing a double-strand break in the genome of a yeast or plant cell, said method comprising:
 a) contacting at least one plant or yeast cell comprising in its genome a meganuclease recognition site with a variant meganuclease polypeptide selected from the group consisting of SEQ ID NOs: 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 251, 252, 253, 272, 273, 274, 275, 272, 273, 274, 275, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402 and 403, wherein the variant meganuclease is capable of inducing a double-strand break in said recognition site; and,   b) selecting the yeast or plant cell from a) and screening said yeast or plant cell for any modification of said recognition sequence.   
     
     
         74 . A method of integrating a polynucleotide of interest into a recognition site in the genome of a plant or yeast cell, the method comprising:
 a) contacting at least one plant or yeast cell comprising in its genome a meganuclease recognition site with:
 (i) a variant meganuclease polypeptide selected from the group consisting of SEQ ID NOs: 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 251, 252, 253, 272, 273, 274, 275, 272, 273, 274, 275, 284, 285, 286, 287, 288, 289, 290, 291, 292, 293, 294, 295, 296, 297, 298, 330, 331, 332, 333, 334, 335, 336, 337, 338, 339, 340, 341, 357, 358, 359, 360, 361, 362, 363, 364, 365, 366, 367, 368, 369, 370, 371, 390, 391, 392, 393, 394, 395, 396, 397, 398, 399, 400, 401, 402 and 403, 
 wherein the variant meganuclease is capable of inducing a double-strand break in said recognition site; and, 
 (ii) a DNA fragment containing a polynucleotide of interest; 
   b) selecting at least one plant or yeast cell comprising integration of the polynucleotide of interest cassette at the recognition site.   
     
     
         75 - 77 . (canceled)