Recycling of a regulatory protein by degradation of the RNA to which it binds

AUTOR(ES)

Deikus, Gintaras

FONTE

National Academy of Sciences

RESUMO

When Bacillus subtilis is grown in the presence of excess tryptophan, transcription of the trp operon is regulated by binding of tryptophan-activated TRAP to trp leader RNA, which promotes transcription termination in the trp leader region. Transcriptome analysis of a B. subtilis strain lacking polynucleotide phosphorylase (PNPase; a 3′-to-5′ exoribonuclease) revealed a striking overexpression of trp operon structural genes when the strain was grown in the presence of abundant tryptophan. Analysis of trp leader RNA in the PNPase- strain showed accumulation of a stable, TRAP-protected fragment of trp leader RNA. Loss of trp operon transcriptional regulation in the PNPase- strain was due to the inability of ribonucleases other than PNPase to degrade TRAP-bound leader RNA, resulting in the sequestration of limiting TRAP. Thus, in the case of the B. subtilis trp operon, specific ribonuclease degradation of RNA in an RNA–protein complex is required for recycling of an RNA-binding protein. Such a mechanism may be relevant to other systems in which limiting concentrations of an RNA-binding protein must keep pace with ongoing transcription.

Documentos Relacionados

• Purification of mouse MEP-1, a nuclear protein which binds to the metal regulatory elements of genes encoding metallothionein.
• A cytosolic protein binds to structural elements within the iron regulatory region of the transferrin receptor mRNA.
• The bacteriophage T4 regulatory protein gpunf/alc binds to DNA in the absence of RNA polymerase.
• Requirements for iron-regulated degradation of the RNA binding protein, iron regulatory protein 2.
• A protein which specifically binds to single stranded TTAGGGn repeats.