Recruitment of the ArgR/Mcm1p repressor is stimulated by the activator Gcn4p: A self-checking activation mechanism

AUTOR(ES)

Yoon, Sungpil

FONTE

National Academy of Sciences

RESUMO

Transcription of the arginine biosynthetic gene ARG1 is repressed by the ArgR/Mcm1p complex in arginine-replete cells and activated by Gcn4p, a transcription factor induced by starvation for any amino acid. We show that all four subunits of the arginine repressor are recruited to ARG1 by Gcn4p in cells replete with arginine but starved for isoleucine/valine. None of these proteins is recruited to the Gcn4p target genes ARG4 and SNZ1, which are not regulated by ArgR/Mcm1p. Mcm1p and Arg80p were found in a soluble complex lacking Arg81p and Arg82p, and both Mcm1p and Arg80p were efficiently recruited to ARG1 in wild-type cells in the presence or absence of exogenous arginine, and also in arg81Δ cells. By contrast, the recruitment of Arg81p and Arg82p was stimulated by exogenous arginine. These findings suggest that Gcn4p constitutively recruits an Mcm1p/Arg80p heterodimer and that efficient assembly of a functional repressor also containing Arg81p and Arg82p occurs only in arginine excess. By recruiting an arginine-regulated repressor, Gcn4p can precisely modulate its activation function at ARG1 according to the availability of arginine.

Documentos Relacionados

• UM MICROCOMPUTADOR AUTO-DIAGNOSTICÁVEL
• Design of self-checking fully differential circuits and boards
• A self-checking scheme to mitigate single event upset effects in SRAM-based FPAAs
• The E2 Ubiquitin Conjugase Rad6 Is Required for the ArgR/Mcm1 Repression of ARG1 Transcription
• ArgRII, a Component of the ArgR-Mcm1 Complex Involved in the Control of Arginine Metabolism in Saccharomyces cerevisiae, Is the Sensor of Arginine