The Essential Transcription Factor, Mcm1, Is a Downstream Target of Sln1, a Yeast "Two-component" Regulator

Abstract

In a search for mutants exhibiting altered activity of the yeast transcription factor, Mcm1, we have identified the SLN1 gene, whose product is highly related to bacterial two-component sensor-regulator proteins. sln1 alleles identified in our screen increased Mcm1p-mediated transcriptional activation, while deletion of the SLN1 locus severely reduced Mcm1p activity. Our data establish that Mcm1p is a downstream target of the Sln1 signaling pathway. Yeast Sln1p was recently shown to be involved in osmoregulation and to depend on the Hog1 MAP kinase (Maeda, T., Wurgler-Murphy, S., and Saito, H. (1994) Nature 369, 242-245). We show that SLN1-mediated regulation of Mcm1p activity is independent of the Hog1 MAP kinase, and suggest that the role of SLN1 is not restricted to osmoregulation.

Comparative genomics of MAP kinase and calcium–calcineurin signalling components in plant and human pathogenic fungi

“…Downstream targets of Hog1 in S. cerevisiae include the MAPKdependent protein kinases Rck1 and Rck2 (Bilsland et al, 2004), as well as the transcription factors Sko1 (Rep et al, 2001), Msn2 and Msn4 (Martinez-Pastor et al, 1996), Hot1 (Rep et al, 2000), Smp1 and Rlm1 (de Nadal et al, 2003), and Mcm1 (Yu et al, 1995). Our study indicates that all these downstream components are well conserved across the fungal phyla, except for Hot1 whose presence is limited to the Saccharomycotina.…”

Intracellular Glycerol Levels Modulate the Activity of Sln1p, aSaccharomyces cerevisiae Two-component Regulator

“…The P site and mut P site oligonucleotides used in construction of these reporters were as follows: 5Ј-TCGAGTTTCCTA-ATTAGGAAAC-3Ј (P) and 5Ј-TCGAGTTTCCTAATTAATAAAC-3Ј plus 5Ј-TCGAGTTTATTAATTAGGAAAC-3Ј (mutP). LEU2 CEN plasmids used in the genetic screen for new nrp mutants included SLN1 (pGY111) (18), GAL11 (pJF765) (35), and KEX2 (pSBKX, R. Fuller).…”

“…Cytoductants were selected on drug plates (selecting for the persistence of the nrp nucleus and loss of the kar1 nucleus) lacking leucine (selecting for the presence of the plasmid) and tested for their X-gal phenotype. The starting strain, JF1567 was subject to ethyl methanesulfonate mutagenesis (18) sufficient to cause 65% killing. Approximately 54,600 surviving colonies were screened on X-gal plates to find 550 mutants with increased blue color.…”

“…A 5.0 M sorbitol stock was first added to conditioned YPD to a final concentration of 2.0 M. YPD cultures grown to 1 ϫ 10 7 cells/ml were then diluted 1:1 with the 2.0 M conditioned YPD/sorbitol to a final concentration of 1.0 M sorbitol. Preparation of RNA, electrophoresis, blotting, and hybridization were performed as described previously (18). 32 P-Labeled probes were prepared using random primers (39, 40).…”

“…Recently, we have shown that Sln1p also regulates the activity of a Hog1p-independent pathway whose transcriptional output can be monitored using a lacZ reporter gene we call P-lacZ, which consists of a CYC1-lacZ fusion in which the UAS of CYC1 has been replaced by a palindromic-binding site (P site) for the Mcm1p transcription factor (17,18). Potential and known target genes of Mcm1p encode proteins involved in cell type determination, cell wall and membrane integrity, cellular metabolism, and cell cycle progression (19).…”