Caracterización de genes rsf implicados en el control del ciclo celular en levadura
In S. cerevisiae, similarly with mammals cells, the major control point during cell cycle appears at late G1 phase, in a process called Start. In that moment cells decide to initiate or not a new round of cell division. In Start, when enviromental conditions are appropiate and cells reach a critical size, different processes begin such as DNA replication, bud emergence and spindle pole body duplication. One of the mechanisms contributing to cell cycle regulation is the control of transcription. In the budding yeast expression of some 250 genes is thougt to fluctuate throug the cell cycle. The transcription factors responsible for the periodic gene expression in late G1 phase are SBF (Swi4p-Swi6p) and MBF (Mbp1-Swi6p). To further understand Swi4p function, we step up a synthetic lethal screen for genes interacting with SWI4 (Igual et al. 1996). Fourteen conditional mutations which resulted in lethality only in the absence of SWI4 have been isolated. Two of these mutants, rsf12 and msn5swi4, were characterized in details in that work. In rsf12 mutant we were demonstrated a functional link between cyclin Clb5p, PKC pathway and SBF transcription factor in DNA metabolism and cell integrity. Moreover, we were characterized that ROT1 gen is functionally linked to the PKC pathway and is required for proper mitotic exit. In msn5swi4 mutant, we were identified that Msn5p is involved in control of Start, being required specifically for SBF activity but is not affecting MBF function. The karyopherin Msn5p is essential for the export of Swi6p to the cytoplasm during G2-M phases and this regulatory mechanism is acting in every cell cycle.
Advisor:Igual García, Juan Carlos
School:Universitat de València
Source Type:Master's Thesis
Keywords:bioquímica i biologia molecular
Date of Publication:07/25/2003