High impact information on MOT3

• This screen identified PAN1, a gene required for normal endocytosis, and VPS41, a gene required for vacuolar fusion and protein targeting, suggesting a role for Mot3 in the regulation of membrane-related genes [1].
• Taken together, our data suggest that proper transcriptional regulation of ergosterol biosynthetic genes by Mot3 is important for normal vacuolar function and probably for the endocytic membrane transport system [1].
• However, a mot3 Delta mutation causes only mild phenotypes under normal growth conditions [1].
• Ergosterol has been shown to be required for endocytosis and homotypic vacuole fusion, providing a link between Mot3 and these processes [1].
• Consistent with these results, mot3 Delta mutants have a number of related defects, including impaired homotypic vacuole fusion and increased sterol levels [1].

Biological context of MOT3

• One is Rox1, an HMG protein, and the second, originally designated Rox7, is shown here to be Mot3, a global C2H2 zinc finger regulator [2].
• MOT3 was found to be a dosage-dependent inhibitor of pheromone response and pheromone-induced gene expression and to require an intact signaling pathway to exert its effects [3].
• We show here that this difference is due to the presence of a Mot3 binding site in OpA [4].
• We show that Mot3 binds in vitro to three sites within the retrotransposon Ty long terminal repeat (delta) sequence [5].
• These results, in conjunction with those of an independent study of Mot3 (A. Grishin, M. Rothenberg, M. A. Downs, and K. J. Blumer, Genetics, in press), suggest that this protein plays a varied role in gene expression that may be largely redundant with other factors [5].

Associations of MOT3 with chemical compounds

• We report here cross-regulation between Rox1 and Mot3 and Rfx1 in the regulation of the RNR genes encoding ribonucleotide diphosphate reductase [6].

Physical interactions of MOT3

• The Mot3 protein was demonstrated to bind to the ANB1 OpA in vitro [4].
• Chromatin immunoprecipitation assays indicated that Rox1 stabilized Mot3 binding to DNA [7].

Regulatory relationships of MOT3

• In addition, using a Rox1-Ssn6 fusion protein, we demonstrated that Mot3 enhances Rox1 repression through helping recruit the Ssn6/Tup1 complex [7].

Other interactions of MOT3

• Repression of anaerobic genes results from co-induction of Mot3 and Rox1 in aerobic cells [2].
• Moreover, the two repression mechanisms appear to be distinct: as shown here repression of ANB1 by Rox1 alone requires Tup1-Ssn6, whereas repression by Mot3 does not [2].
• Although a mot3 null mutation causes no strong phenotypes, it does cause some mild phenotypes, including a very modest increase in Ty mRNA levels, partial suppression of transcriptional defects caused by a mot1 mutation, and partial suppression of an spt3 mutation [5].
• This nucleosome was absent in cells carrying a rox1, tup1, or mot3 deletion, all of which cause some degree of derepression [4].

References