Overexpression of SIS2, which contains an extremely acidic region, increases the expression of SWI4, CLN1 and CLN2 in sit4 mutants

Genetics. 1995 Jan;139(1):95-107. doi: 10.1093/genetics/139.1.95.


The Saccharomyces cerevisiae SIS2 gene was identified by its ability, when present on a high copy number plasmid, to increase dramatically the growth rate of sit4 mutants. SIT4 encodes a type 2A-related protein phosphatase that is required in late G1 for normal G1 cyclin expression and for bud initiation. Overexpression of SIS2, which contains an extremely acidic carboxyl terminal region, stimulated the rate of CLN1, CLN2, SWI4 and CLB5 expression in sit4 mutants. Also, overexpression of SIS2 in a CLN1 cln2 cln3 strain stimulated the growth rate and the rate of CLN1 and CLB5 RNA accumulation during late G1. The SIS2 protein fractionated with nuclei and was released from the nuclear fraction by treatment with either DNase I or micrococcal nuclease, but not by RNase A. This result, combined with the finding that overexpression of SIS2 is extremely to a strain containing lower than normal levels of histones H2A and H2B, suggests that SIS2 might function to stimulate transcription via an interaction with chromatin.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • Cell Compartmentation
  • Cell Cycle / genetics*
  • Cell Cycle Proteins*
  • Cell Nucleus / chemistry
  • Chromatin / physiology
  • Cyclins / biosynthesis*
  • DNA-Binding Proteins
  • Fungal Proteins / biosynthesis*
  • Fungal Proteins / genetics*
  • Gene Deletion
  • Gene Expression Regulation, Fungal
  • Genes, Fungal / genetics
  • Molecular Sequence Data
  • Mutation
  • Phosphoprotein Phosphatases / genetics
  • Protein Phosphatase 2
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / growth & development
  • Saccharomyces cerevisiae Proteins*
  • Sequence Homology, Amino Acid
  • Transcription Factors*
  • Transcription, Genetic


  • CLN1 protein, S cerevisiae
  • CLN2 protein, S cerevisiae
  • Cell Cycle Proteins
  • Chromatin
  • Cyclins
  • DNA-Binding Proteins
  • Fungal Proteins
  • SIS2 protein, S cerevisiae
  • SWI4 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factors
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 2
  • SIT4 protein, S cerevisiae

Associated data

  • GENBANK/U01878
  • GENBANK/Z28088