Novel Escherichia coli RNA Polymerase Binding Protein Encoded by Bacteriophage T5статья
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Дата последнего поиска статьи во внешних источниках: 11 ноября 2020 г.
Аннотация:The Escherichia coli bacteriophage T5 has three temporal classes of genes
(pre-early, early, and late). All three classes are transcribed by host RNA
polymerase (RNAP) containing the σ70 promoter specificity subunit. Molecular
mechanisms responsible for the switching of viral transcription from one class
to another remain unknown. Here, we find the product of T5 gene 026 (gpT5.026)
in RNAP preparations purified from T5-infected cells and demonstrate in vitro
its tight binding to E. coli RNAP. While proteins homologous to gpT5.026 are
encoded by all T5-related phages, no similarities to proteins with known
functions can be detected. GpT5.026 binds to two regions of the RNAP β subunit
and moderately inhibits RNAP interaction with the discriminator region of
σ70-dependent promoters. A T5 mutant with disrupted gene 026 is viable, but the
host cell lysis phase is prolongated and fewer virus particles are produced.
During the mutant phage infection, the number of early transcripts increases,
whereas the number of late transcripts decreases. We propose that gpT5.026 is
part of the regulatory cascade that orchestrates a switch from early to late
bacteriophage T5 transcription.