Mismatch extension ability of yeast and human DNA polymerase eta.

Abstract:

DNA polymerase eta (Poleta) functions in error-free replication of UV-damaged DNA, and in vitro it efficiently bypasses a cis-syn T-T dimer by incorporating two adenines opposite the lesion. Steady state kinetic studies have shown that both yeast and human Poleta are low-fidelity enzymes, and they misincorporate nucleotides with a frequency of 10(-2)-10(-3) on both undamaged and T-T dimer-containing DNA templates. To better understand the role of Poleta in error-free translesion DNA synthesis, here we examine the ability of Poleta to extend from base mismatches. We find that both yeast and human Poleta extend from mismatched base pairs with a frequency of approximately 10(-3) relative to matched base pairs. In the absence of efficient extension of mismatched primer termini, the ensuing dissociation of Poleta from DNA may favor the excision of mismatched nucleotides by a proofreading exonuclease. Thus, we expect DNA synthesis by Poleta to be more accurate than that predicted from the fidelity of nucleotide incorporation alone.

Polymerases:

Topics:

Status:

new topics/pols set partial results complete validated

Results:

No results available for this paper.

Entry validated by:

Log in to edit reference All References

Using Polbase tables:

Sorting:

Tables may be sorted by clicking on any of the column titles. A second click reverses the sort order. <Ctrl> + click on the column titles to sort by more than one column (e.g. family then name).

Filtering:

It is also possible to filter the table by typing into the search box above the table. This will instantly hide lines from the table that do not contain your search text.