Formation of termination-resistant transcription complex at phage lambda nut locus: effects of altered translation and a ribosomal mutation.

AUTOR(ES)

Warren, F

RESUMO

Transcription antitermination by lambda N gene product is affected in a mutant Escherichia coli with altered ribosomal protein S10, caused by the nusE71 mutation. To study the role of translation in antitermination, we have fused the phage nutR locus, the site of action of N, with the lac regulatory region. We have monitored N action by measuring galactokinase, whose synthesis depends on suppression of terminators located between nutR and the galK cistron. We show that a deletion removing potential ribosome binding signals and AUG codons from the upstream region of nut site does not affect N action. Moreover, the lack of translation upstream of nutR does not overcome the antitermination defect caused by nusE mutation. When the upstream region is translated, however, N action is impaired if translation terminates 19 base pairs upstream of nutR . Termination of translation at further upstream sites, such as 23 or 97 base pairs upstream, does not interfere with N action. Our results suggest that the S10 ribosomal protein is required for N action without involving translation. These results also suggest that the nut site RNA itself plays an important role in the formation of a termination-resistant transcription complex.

Documentos Relacionados

• Control of transcription processivity in phage lambda: Nus factors strengthen the termination-resistant state of RNA polymerase induced by N antiterminator.
• RNA polymerase mutations that impair conversion to a termination-resistant complex by Q antiterminator proteins
• Transcription termination and late control in phage lambda.
• Mutations of the phage lambda nutL region that prevent the action of Nun, a site-specific transcription termination factor.
• Analysis of nutR, a site required for transcription antitermination in phage lambda.