Thermostable reverse transcriptases and uses thereof
The present invention is in the fields of molecular and cellular biology. The invention is generally related to reverse transcriptase enzymes and methods for the reverse transcription of nucleic acid molecules, especially messenger RNA molecules. Specifically, the invention relates to reverse transcriptase enzymes which have been mutated or modified to increase thermostability, decrease terminal deoxynucleotidyl transferase activity, and/or increase fidelity, and to methods of producing, amplifying or sequencing nucleic acid molecules (particularly cDNA molecules) using these reverse transcriptase enzymes or compositions. The invention also relates to nucleic acid molecules produced by these methods and to the use of such nucleic acid molecules to produce desired polypeptides. The invention also concerns kits comprising such enzymes or compositions.
1 . A mutant reverse transcriptase having one or more modifications or mutations at positions corresponding to amino acids selected from the group consisting of:
(a) leucine 52 of M-MLV reverse transcriptase;
(b) tyrosine 64 of M-MLV reverse transcriptase;
(c) lysine 152 of M-MLV reverse transcriptase;
(d) histidine 204 of M-MLV reverse transcriptase;
(e) methionine 289 of M-MLV reverse transcriptase;
(f) threonine 306 of M-MLV reverse transcriptase; and
(g) phenylalanine 309 of M-MLV reverse transcriptase,
wherein said reverse transcriptase synthesizes at least 50% as much full length cDNA at 50° C. as at it does at 40° C.
2 . The reverse transcriptase of claim 1 , which synthesizes at least 70% as much full length cDNA at 50° C. as it does at 40° C.
3 . The reverse transcriptase of claim 1 , which synthesizes at least 80% as much full length cDNA at 50° C. as at it does at 40° C.
4 . The reverse transcriptase of claim 1 , which synthesizes at least 90% as much full length cDNA at 50° C. as at it does at 40° C.
5 . The reverse transcriptase of claim 1 , wherein the reverse transcriptase is M-MLV.
6 . A mutant reverse transcriptase having one or more modifications or mutations at positions corresponding to amino acids selected from the group consisting of:
(a) leucine 52 of M-MLV reverse transcriptase;
(b) tyrosine 64 of M-MLV reverse transcriptase;
(c) lysine 152 of M-MLV reverse transcriptase;
(d) histidine 204 of M-MLV reverse transcriptase;
(e) methionine 289 of M-MLV reverse transcriptase;
(f) threonine 306 of M-MLV reverse transcriptase; and
(g) phenylalanine 309 of M-MLV reverse transcriptase,
wherein said reverse transcriptase synthesizes at least 20% as much full length cDNA at 52.5° C. as at it does at 40° C.
7 . The reverse transcriptase of claim 6 , which synthesizes at least 40% as much full length cDNA at 52.5° C. as at it does at 40° C.
8 . The reverse transcriptase of claim 6 , which synthesizes at least 50% as much full length cDNA at 52.5° C. as at it does at 40° C.
9 . The reverse transcriptase of claim 6 , which synthesizes at least 60% as much full length cDNA at 52.5° C. as at it does at 40° C.
10 . The reverse transcriptase of claim 6 , wherein the reverse transcriptase is M-MLV.
11 . A mutant reverse transcriptase having one or more modifications or mutations at positions corresponding to amino acids selected from the group consisting of:
(a) leucine 52 of M-MLV reverse transcriptase;
(b) tyrosine 64 of M-MLV reverse transcriptase;
(c) lysine 152 of M-MLV reverse transcriptase;
(d) histidine 204 of M-MLV reverse transcriptase;
(e) methionine 289 of M-MLV reverse transcriptase;
(f) threonine 306 of M-MLV reverse transcriptase; and
(g) phenylalanine 309 of M-MLV reverse transcriptase,
wherein said reverse transcriptase synthesizes at least 1% as much full length cDNA at 55° C. as at it does at 40° C.
12 . The reverse transcriptase of claim 11 , which synthesizes at least 5% as much full length cDNA at 55° C. as at it does at 40° C.
13 . The reverse transcriptase of claim 11 , which synthesizes at least 10% as much full length cDNA at 55° C. as at it does at 40° C.
14 . The reverse transcriptase of claim 11 , which synthesizes at least 20% as much full length cDNA at 55° C. as at it does at 40° C.
15 . The reverse transcriptase of claim 11 , wherein the reverse transcriptase is M-MLV.