engleski

The retinoblastoma family of proteins function as direct transcriptional repressors in Saccharomyces cerevisiae

The members of the retinoblastoma family of proteins (the retinoblastoma protein, p107 and p130) are key cell cycle regulators, important for the differentiation of various mammalian cell types. The loss of heterozygosity at the RB1 locus (the gene for the retinoblastoma protein) is in conjunction with the development of retinoblastoma, and inactivation or mutations in the RB1 gene have been detected in number of other cancers. The retinoblastoma family of proteins regulates transcription of a variety of genes, primarily by repression, either by blocking the activation domains of transcriptional factors (eg. via interactions with activators of E2F family) or directly, by own intrinsic repressive activity. We have show that the retinoblastoma protein, p107 and p130 function as direct transcriptional repressors in a yeast Saccharomyces cerevisiae system when fused to the DNA binding domain of pGal4. Either the A or the B domain of the “ pocket region” is necessary and sufficient for repression, though in mammalian cells the repressing motif is formed through interactions of both domains. As is the case in mammalian cells, a phosphorylation mutant of the retinoblastoma protein is a stronger transcriptional repressor than the wild type protein, so it’ s conferred tha hypophosphorilated form is, in fact, active repressor.

transcription; retinoblastoma protein

nije evidentirano