Polκ κ κ κ is one of many DNA polymerases involved in translesion DNA synthesis (TLS). It belongs to the Y-family of polymerases along with Polη η η η, Polι ι ι ι and hREV1. Unlike Polη η η η encoded by the xeroderma pigmentosum variant (XPV ) gene, Polκ κ κ κ is unable to bypass UV-induced DNA damage in vitro, but it is able to bypass benzo[a]pyrene (B[a]P)-adducted guanines accurately and efficiently. In an attempt to identify factor(s) targeting Polκ κ κ κ to its cognate DNA lesion(s), we searched for Polκ κ κ κ-interacting proteins by using the yeast two-hybrid assay. We found that Polκ κ κ κ interacts with a C-terminal region of hREV1. Polη η η η and Polι ι ι ι were also found to interact with the same region of hREV1. The interaction between Polκ κ κ κ and hREV1 was confirmed by pull-down and coimmunoprecipitation assays. The C-terminal region of hREV1 is known to interact with hREV7, a non-catalytic subunit of Polζ ζ ζ ζ that is another structurally unrelated TLS enzyme, and we show that Polκ κ κ κ and hREV7 bind to the same C-terminal region of hREV1. Thus, our results suggest that hREV1 plays a pivotal role in the multi-enzyme, multi-step process of translesion DNA synthesis.

No abstract

We found two genes for tRNA(Arg) in the region upstream of genes for Shiga-like toxin type II (SLT-II) in Escherichia coli O157:H7. The two encoded forms of tRNA(Arg) recognize rare codons in E. coli K12 but these rare codons occur in the toxin genes at high frequency.

No abstract