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PMID:22566619

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Citation

Zhu, B, Lee, SJ, Tan, M, Wang, ED and Richardson, CC (2012) Gene 5.5 protein of bacteriophage T7 in complex with Escherichia coli nucleoid protein H-NS and transfer RNA masks transfer RNA priming in T7 DNA replication. Proc. Natl. Acad. Sci. U.S.A. 109:8050-5

Abstract

DNA primases provide oligoribonucleotides for DNA polymerase to initiate lagging strand synthesis. A deficiency in the primase of bacteriophage T7 to synthesize primers can be overcome by genetic alterations that decrease the expression of T7 gene 5.5, suggesting an alternative mechanism to prime DNA synthesis. The product of gene 5.5 (gp5.5) forms a stable complex with the Escherichia coli histone-like protein H-NS and transfer RNAs (tRNAs). The 3'-terminal sequence (5'-ACCA-3') of tRNAs is identical to that of a functional primer synthesized by T7 primase. Mutations in T7 that suppress the inability of primase reduce the amount of gp5.5 and thus increase the pool of tRNA to serve as primers. Alterations in T7 gene 3 facilitate tRNA priming by reducing its endonuclease activity that cleaves at the tRNA-DNA junction. The tRNA bound to gp5.5 recruits H-NS. H-NS alone inhibits reactions involved in DNA replication, but the binding to gp5.5-tRNA complex abolishes this inhibition.

Links

PubMed PMC3361414 Online version:10.1073/pnas.1205990109

Keywords

Bacteriophage T7/genetics; DNA Helicases/metabolism; DNA Primase/metabolism; DNA Primers/genetics; DNA Replication/genetics; Endonucleases/metabolism; Escherichia coli/genetics; Escherichia coli/virology; Escherichia coli Proteins/genetics; Fimbriae Proteins/genetics; Gene Expression Regulation, Viral/physiology; Plasmids/genetics; RNA, Transfer/genetics; Viral Proteins/genetics

Significance

Annotations

Gene product Qualifier GO Term Evidence Code with/from Aspect Extension Notes Status

BPT7:V5557

Contributes to

GO:0006944: cellular membrane fusion

ECO:0000316:

UniProtKB:P03787


P

T7 replication yielding HN-S inhibition and production. Inhibition of phage growth in cell. Assists in fusion and plating

complete
CACAO 12627

Notes

See also

References

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