title: SPN1, a conserved gene identified by suppression of a postrecruitment-defective yeast TATA-binding protein mutant.
abstract: Little is known about TATA-binding protein (TBP) functions after recruitment to the TATA element, although several TBP mutants display postrecruitment defects. Here we describe a genetic screen for suppressors of a postrecruitment-defective TBP allele. Suppression was achieved by a single point mutation in a previously uncharacterized Saccharomyces cerevisiae gene, SPN1 (suppresses postrecruitment functions gene number 1). SPN1 is an essential yeast gene that is highly conserved throughout evolution. The suppressing mutation in SPN1 substitutes an asparagine for an invariant lysine at position 192 (spn1(K192N)). The spn1(K192N) strain is able to suppress additional alleles of TBP that possess postrecruitment defects, but not a TBP allele that is postrecruitment competent. In addition, Spn1p does not stably associate with TFIID in vivo. Cells containing the spn1(K192N) allele exhibit a temperature-sensitive phenotype and some defects in activated transcription, whereas constitutive transcription appears relatively robust in the mutant background. Consistent with an important role in postrecruitment functions, transcription from the CYC1 promoter, which has been shown to be regulated by postrecruitment mechanisms, is enhanced in spn1(K192N) cells. Moreover, we find that SPN1 is a member of the SPT gene family, further supporting a functional requirement for the SPN1 gene product in transcriptional processes.
authors.affiliation: Department of Biochemistry and Molecular Biology, Colorado State University, Fort Collins, Colorado 80523-1870, USA.
authors.forename: Julie A
authors.initials: JA
authors.lastname: Fischbeck
authors.forename: Susan M
authors.initials: SM
authors.lastname: Kraemer
authors.forename: Laurie A
authors.initials: LA
authors.lastname: Stargell
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D003574:Cytochrome c Group / Q000235:genetics; D045304:Cytochromes c; D019143:Evolution, Molecular; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D005810:Multigene Family; D009154:Mutation; D010641:Phenotype; D011401:Promoter Regions, Genetic; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013489:Suppression, Genetic; D035181:TATA-Box Binding Protein / Q000031:analogs & derivatives / Q000235:genetics* / Q000378:metabolism*; D015533:Transcriptional Activation
chemical_list: C014059:CYC1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D003574:Cytochrome c Group; C475586:SPN1 protein, S cerevisiae; C115017:SPT15 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D035181:TATA-Box Binding Protein; D045304:Cytochromes c