Bacteriophage T7 protein kinase phosphorylates RNase E and stabilizes mRNAs synthesized by T7 RNA polymerase

Citation
I. Marchand et al., Bacteriophage T7 protein kinase phosphorylates RNase E and stabilizes mRNAs synthesized by T7 RNA polymerase, MOL MICROB, 42(3), 2001, pp. 767-776
Citations number
41
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
MOLECULAR MICROBIOLOGY
ISSN journal
0950-382X → ACNP
Volume
42
Issue
3
Year of publication
2001
Pages
767 - 776
Database
ISI
SICI code
0950-382X(200111)42:3<767:BTPKPR>2.0.ZU;2-0
Abstract
The T7 protein encoded by the early gene 0.7 exhibits bifunctional activity . Whereas its C-terminal one-third participates in host transcription shut- off, the N-terminal two-thirds bears a protein kinase ('PK') activity that can phosphorylate a number of host proteins in addition to itself. Here, we show that, when PK is expressed in uninfected Escherichia coli cells, the C-terminal half of RNase E and the associated RNA helicase RhIB are heavily phosphorylated. Meanwhile, a subset of RNase E substrates, including the l ac and cat mRNAs synthesized by bacteriophage T7 RNA polymerase (RNAP), are stabilized. These mRNAs are genuinely less stable than their counterparts synthesized by E. coil RNAP, because T7 RNAP outpaces translating ribosomes , creating naked, RNase E-sensitive mRNA stretches behind itself. Thus, PK alleviates this effect of desynchronizing transcription and translation. Th e relationship between the modification of RNase E and RhIB and these mRNA stabilization effects, which may be relevant to the stability of late T7 mR NAs during infection, is discussed.