Yeast calmodulin and a conserved nuclear protein participate in the in vivo binding of a matrix association region.
Chromatin becomes reorganized during mitosis each cell cycle. To identify genes potentially involved in these supramolecular events, we have used a colony-color assay to screen temperature-sensitive mutants of Saccharomyces cerevisiae. When a sequence that mediates attachment to the nuclear matrix in vitro was inserted into the GAL1 promoter of a lacZ fusion gene, beta-galactosidase synthesis was inhibited. This observation permitted screening for temperature-sensitive-inducible mutants on 5-bromo-4-chloro-3-indolyl beta-D-galactoside plates. Only 1 of 20 complementation groups of newly isolated mutants exhibited temperature-sensitive inducibility for the matrix association region but not for control CEN3 or STE6 inserts--a cmd1 mutant in which the last 7 amino acids of calmodulin were truncated by an ochre termination codon. Another mutant (smi1) exhibited a rare phenotype at the nonpermissive condition, which included S phase and budding arrest. We cloned and sequenced the SMI1 gene, which encodes a 57-kDa polypeptide with evolutionarily conserved epitope(s) found in mammalian cell nuclei. Thus, we provide evidence for involvement of calmodulin and another conserved protein in the in vivo binding of a matrix association region.
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
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Fishel
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Sperry
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Garrard
D000595:Amino Acid Sequence; D000818:Animals; D000906:Antibodies; D001483:Base Sequence; D005075:Biological Evolution; D002147:Calmodulin / Q000378:metabolism*; D002467:Cell Nucleus / Q000378:metabolism*; D003001:Cloning, Molecular; D017124:Conserved Sequence; D005800:Genes, Fungal; D005816:Genetic Complementation Test; D008322:Mammals; D008969:Molecular Sequence Data; D016296:Mutagenesis; D015530:Nuclear Matrix / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis / Q000276:immunology; D011401:Promoter Regions, Genetic; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D013696:Temperature; D014157:Transcription Factors; D001616:beta-Galactosidase / Q000096:biosynthesis
D000906:Antibodies; D002147:Calmodulin; D009687:Nuclear Proteins; D010455:Peptides; D011993:Recombinant Fusion Proteins; C085451:SMI1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D001616:beta-Galactosidase