Conservation of Glutamine-Rich Transactivation Function between Yeast and Humans

AUTOR(ES)

Escher, Dominik

FONTE

American Society for Microbiology

RESUMO

Several eukaryotic transcription factors such as Sp1 or Oct1 contain glutamine-rich domains that mediate transcriptional activation. In human cells, promoter-proximally bound glutamine-rich activation domains activate transcription poorly in the absence of acidic type activators bound at distal enhancers, but synergistically stimulate transcription with these remote activators. Glutamine-rich activation domains were previously reported to also function in the fission yeast Schizosaccharomyces pombe but not in the budding yeast Saccharomyces cerevisiae, suggesting that budding yeast lacks this pathway of transcriptional activation. The strong interaction of an Sp1 glutamine-rich domain with the general transcription factor TAFII110 (TAFII130), and the absence of any obvious TAFII110 homologue in the budding yeast genome, seemed to confirm this notion. We reinvestigated the phenomenon by reconstituting in the budding yeast an enhancer-promoter architecture that is prevalent in higher eukaryotes but less common in yeast. Under these conditions, we observed that glutamine-rich activation domains derived from both mammalian and yeast transcription factors activated only poorly on their own but strongly synergized with acidic activators bound at the remote enhancer position. The level of activation by the glutamine-rich activation domains of Sp1 and Oct1 in combination with a remote enhancer was similar in yeast and human cells. We also found that mutations in a glutamine-rich domain had similar phenotypes in budding yeast and human cells. Our results show that glutamine-rich activation domains behave very similarly in yeast and mammals and that their activity in budding yeast does not depend on the presence of a TAFII110 homologue.

Documentos Relacionados

• An alternatively spliced form of the transcription factor Sp1 containing only a single glutamine-rich transactivation domain.
• An inhibitor domain in Sp3 regulates its glutamine-rich activation domains.
• Normal Myeloid Development Requires Both the Glutamine-Rich Transactivation Domain and the PEST Region of Transcription Factor PU.1 but Not the Potent Acidic Transactivation Domain
• Expression, purification and preliminary crystallographic analysis of recombinant human small glutamine-rich tetratricopeptide-repeat protein
• A direct interaction between a glutamine-rich activator and the N terminus of TFIIB can mediate transcriptional activation in vivo.