Mutations in a small region of the exportin Crm1p disrupt the daughter cell-specific nuclear localization of the transcription factor Ace2p in Saccharomyces cerevisiae.

Background Information: The CBK1 gene of Saccharomyces cerevisiae encodes a protein kinase that is a member of the NDR (nuclear Dbf2-related) family of protein kinases, which are involved in morphogenesis and cell proliferation. Previous studies have shown that deletion of CBK1 leads to a loss of polarity and the formation of large aggregates of cells. This aggregation phenotype is due to the loss of the daughter cell-specific accumulation of the transcription factor Ace2p, which is responsible for the transcription of genes whose products are necessary for the final separation of the mother and the daughter at the end of cell division.

Aerobic and anaerobic NAD+ metabolism in Saccharomyces cerevisiae.

In Saccharomyces cerevisiae the nicotinic acid moiety of NAD+ can be synthesized from tryptophan using the kynurenine pathway or incorporated directly using nicotinate phosphoribosyl transferase (NPT1). We have identified the genes that encode the enzymes of the kynurenine pathway and for BNA5 (YLR231c) and BNA6 (YFR047c) confirmed that they encode kynureninase and quinolinate phosphoribosyl transferase respectively. We show that deletion of genes encoding kynurenine pathway enzymes are co-lethal with the Deltanpt1, demonstrating that no other pathway for the synthesis of nicotinic acid exists in S.