The frameshift infidelity of human DNA polymerase lambda. Implications for function.

Abstract:

DNA polymerase lambda (Pol lambda) is a member of the Pol X family having properties in common with several other mammalian DNA polymerases. To obtain clues to possible functions in vivo, we have determined the fidelity of DNA synthesis by human Pol lambda. The results indicate that the average single-base deletion error rate of Pol lambda is higher than those of other mammalian polymerases. In fact, unlike other DNA polymerases, Pol lambda generates single-base deletions at average rates that substantially exceed base substitution rates. Moreover, the sequence specificity for single-base deletions made by Pol lambda is different from that of other DNA polymerases and reveals that Pol lambda readily uses template-primers with limited base pair homology at the primer terminus. This ability, together with an ability to fill short gaps in DNA at low dNTP concentrations, is consistent with a role for mammalian Pol lambda in non-homologous end-joining. This may include non-homologous end-joining of strand breaks resulting from DNA damage, because Pol lambda has intrinsic 5',2'-deoxyribose-5-phosphate lyase activity.

Polymerases:

Topics:

Fidelity, Nucleotide Incorporation, Exonuclease Activity, Terminal Transferase

Status:

new topics/pols set partial results complete validated

Results:

Polymerase Reference Property Result Context
Human Pol lamba Bebenek K2003 Terminal Transferase No
Human Pol lamba Bebenek K2003 3-5' Exonuclease (proofreading) No
Human Pol lamba Bebenek K2003 Frameshift Error Rate 0.0049 errors/bp Technique: M13mp2 forward mutation assay
Human Pol lamba Bebenek K2003 Nucleotide Substitution Rate 0.0009 errors/bp Technique: M13mp2 forward mutation assay
Human Pol lamba Bebenek K2003 Full length or truncated Full length
Human Pol lamba Bebenek K2003 Gap Filling Yes

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