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. 1990 Jun;125(2):321–331. doi: 10.1093/genetics/125.2.321

Extragenic Suppressors of Mar2(sir3) Mutations in Saccharomyces Cerevisiae

CIP Lin 1, G P Livi 1, J M Ivy 1, AJS Klar 1
PMCID: PMC1204022  PMID: 2199314

Abstract

The silent mating-type genes (HML and HMR) of Saccharomyces cerevisiae are kept under negative transcriptional control by four trans-acting MAR (or SIR) loci. We have isolated extragenic suppressors of the mar2-1 mutation which, based on genetic complementation tests, define two additional loci involved in regulating the expression of HML and HMR. A strain with the genotype HMLa MATα HMRa mar2-1 is sterile due to the simultaneous expression of a and α information. Two mutants exhibiting an α phenotype (which may result from the restoration of MAR/SIR repression) were isolated and genetically characterized. The mutations in these strains: (1) are recessive, (2) are capable of suppressing a mar2-deletion mutation, (3) are unlinked to MAT, (4) complement one another as well as the previously identified sum1-1 mutation, and (5) are not new alleles of the known MAR/SIR loci. We designate these new regulatory loci SUM2 and SUM3 (supressor of mar). Unlike the sum1-1 mutation, suppression by sum2-1 and sum3-1 is mar2-locus specific. Both sum2-1 and sum3-1 affect the expression of a information at the HM loci. Transcript analysis shows a significant reduction in HMLa and HMRa gene transcription in mar2-1 sum2-1 and mar2-1 sum3-1 cells. Furthermore, we have found genetic evidence to suggest that mar2-1 sum2-1 cells exhibit only partial expression of silent α information. We conclude that the SUM2 and SUM3 gene products are required for expression of the HM loci and act downstream of the MAR2 (SIR3) gene function. Possible mechanisms for the action of the SUM gene products are discussed.

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Selected References

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  1. Abraham J., Nasmyth K. A., Strathern J. N., Klar A. J., Hicks J. B. Regulation of mating-type information in yeast. Negative control requiring sequences both 5' and 3' to the regulated region. J Mol Biol. 1984 Jul 5;176(3):307–331. doi: 10.1016/0022-2836(84)90492-3. [DOI] [PubMed] [Google Scholar]
  2. Aviv H., Leder P. Purification of biologically active globin messenger RNA by chromatography on oligothymidylic acid-cellulose. Proc Natl Acad Sci U S A. 1972 Jun;69(6):1408–1412. doi: 10.1073/pnas.69.6.1408. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Beggs J. D. Transformation of yeast by a replicating hybrid plasmid. Nature. 1978 Sep 14;275(5676):104–109. doi: 10.1038/275104a0. [DOI] [PubMed] [Google Scholar]
  4. Brand A. H., Breeden L., Abraham J., Sternglanz R., Nasmyth K. Characterization of a "silencer" in yeast: a DNA sequence with properties opposite to those of a transcriptional enhancer. Cell. 1985 May;41(1):41–48. doi: 10.1016/0092-8674(85)90059-5. [DOI] [PubMed] [Google Scholar]
  5. Brand A. H., Micklem G., Nasmyth K. A yeast silencer contains sequences that can promote autonomous plasmid replication and transcriptional activation. Cell. 1987 Dec 4;51(5):709–719. doi: 10.1016/0092-8674(87)90094-8. [DOI] [PubMed] [Google Scholar]
  6. Broach J. R., Li Y. Y., Feldman J., Jayaram M., Abraham J., Nasmyth K. A., Hicks J. B. Localization and sequence analysis of yeast origins of DNA replication. Cold Spring Harb Symp Quant Biol. 1983;47(Pt 2):1165–1173. doi: 10.1101/sqb.1983.047.01.132. [DOI] [PubMed] [Google Scholar]
  7. Buchman A. R., Kimmerly W. J., Rine J., Kornberg R. D. Two DNA-binding factors recognize specific sequences at silencers, upstream activating sequences, autonomously replicating sequences, and telomeres in Saccharomyces cerevisiae. Mol Cell Biol. 1988 Jan;8(1):210–225. doi: 10.1128/mcb.8.1.210. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Carlson M., Botstein D. Two differentially regulated mRNAs with different 5' ends encode secreted with intracellular forms of yeast invertase. Cell. 1982 Jan;28(1):145–154. doi: 10.1016/0092-8674(82)90384-1. [DOI] [PubMed] [Google Scholar]
  9. Feldman J. B., Hicks J. B., Broach J. R. Identification of sites required for repression of a silent mating type locus in yeast. J Mol Biol. 1984 Oct 5;178(4):815–834. doi: 10.1016/0022-2836(84)90313-9. [DOI] [PubMed] [Google Scholar]
  10. Haber J. E., George J. P. A mutation that permits the expression of normally silent copies of mating-type information in Saccharomyces cerevisiae. Genetics. 1979 Sep;93(1):13–35. doi: 10.1093/genetics/93.1.13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Harashima S., Oshima Y. Mapping of the homothallic genes, HM alpha and HMa, in Saccharomyces yeasts. Genetics. 1976 Nov;84(3):437–451. doi: 10.1093/genetics/84.3.437. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Hicks J. B., Herskowitz I. Interconversion of Yeast Mating Types I. Direct Observations of the Action of the Homothallism (HO) Gene. Genetics. 1976 Jun;83(2):245–258. doi: 10.1093/genetics/83.2.245. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hicks J., Strathern J. N., Klar A. J. Transposable mating type genes in Saccharomyces cerevisiae. Nature. 1979 Nov 29;282(5738):478–473. doi: 10.1038/282478a0. [DOI] [PubMed] [Google Scholar]
  14. Ivy J. M., Klar A. J., Hicks J. B. Cloning and characterization of four SIR genes of Saccharomyces cerevisiae. Mol Cell Biol. 1986 Feb;6(2):688–702. doi: 10.1128/mcb.6.2.688. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kayne P. S., Kim U. J., Han M., Mullen J. R., Yoshizaki F., Grunstein M. Extremely conserved histone H4 N terminus is dispensable for growth but essential for repressing the silent mating loci in yeast. Cell. 1988 Oct 7;55(1):27–39. doi: 10.1016/0092-8674(88)90006-2. [DOI] [PubMed] [Google Scholar]
  16. Kimmerly W. J., Rine J. Replication and segregation of plasmids containing cis-acting regulatory sites of silent mating-type genes in Saccharomyces cerevisiae are controlled by the SIR genes. Mol Cell Biol. 1987 Dec;7(12):4225–4237. doi: 10.1128/mcb.7.12.4225. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Kimmerly W., Buchman A., Kornberg R., Rine J. Roles of two DNA-binding factors in replication, segregation and transcriptional repression mediated by a yeast silencer. EMBO J. 1988 Jul;7(7):2241–2253. doi: 10.1002/j.1460-2075.1988.tb03064.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  18. Klar A. J., Fogel S. Activation of mating type genes by transposition in Saccharomyces cerevisiae. Proc Natl Acad Sci U S A. 1979 Sep;76(9):4539–4543. doi: 10.1073/pnas.76.9.4539. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Klar A. J., Fogel S., Macleod K. MAR1-a Regulator of the HMa and HMalpha Loci in SACCHAROMYCES CEREVISIAE. Genetics. 1979 Sep;93(1):37–50. doi: 10.1093/genetics/93.1.37. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Klar A. J., Fogel S., Radin D. N. Switching of a mating-type a mutant allele in budding yeast Saccharomyces cerevisiae. Genetics. 1979 Jul;92(3):759–776. doi: 10.1093/genetics/92.3.759. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Klar A. J. Interconversion of yeast cell types by transposable genes. Genetics. 1980 Jul;95(3):631–648. doi: 10.1093/genetics/95.3.631. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Klar A. J., Kakar S. N., Ivy J. M., Hicks J. B., Livi G. P., Miglio L. M. SUM1, an apparent positive regulator of the cryptic mating-type loci in Saccharomyces cerevisiae. Genetics. 1985 Dec;111(4):745–758. doi: 10.1093/genetics/111.4.745. [DOI] [PMC free article] [PubMed] [Google Scholar]
  23. Klar A. J., McIndoo J., Hicks J. B., Strathern J. N. Precise mapping of the homothallism genes HML and HMR in Saccharomyces cerevisiae. Genetics. 1980 Oct;96(2):315–320. doi: 10.1093/genetics/96.2.315. [DOI] [PMC free article] [PubMed] [Google Scholar]
  24. Klar A. J., Strathern J. N., Broach J. R., Hicks J. B. Regulation of transcription in expressed and unexpressed mating type cassettes of yeast. Nature. 1981 Jan 22;289(5795):239–244. doi: 10.1038/289239a0. [DOI] [PubMed] [Google Scholar]
  25. Klar A. J., Strathern J. N., Hicks J. B. A position-effect control for gene transposition: state of expression of yeast mating-type genes affects their ability to switch. Cell. 1981 Aug;25(2):517–524. doi: 10.1016/0092-8674(81)90070-2. [DOI] [PubMed] [Google Scholar]
  26. Kostriken R., Heffron F. The product of the HO gene is a nuclease: purification and characterization of the enzyme. Cold Spring Harb Symp Quant Biol. 1984;49:89–96. doi: 10.1101/sqb.1984.049.01.012. [DOI] [PubMed] [Google Scholar]
  27. Kostriken R., Strathern J. N., Klar A. J., Hicks J. B., Heffron F. A site-specific endonuclease essential for mating-type switching in Saccharomyces cerevisiae. Cell. 1983 Nov;35(1):167–174. doi: 10.1016/0092-8674(83)90219-2. [DOI] [PubMed] [Google Scholar]
  28. Kushner P. J., Blair L. C., Herskowitz I. Control of yeast cell types by mobile genes: a test. Proc Natl Acad Sci U S A. 1979 Oct;76(10):5264–5268. doi: 10.1073/pnas.76.10.5264. [DOI] [PMC free article] [PubMed] [Google Scholar]
  29. Lehrach H., Diamond D., Wozney J. M., Boedtker H. RNA molecular weight determinations by gel electrophoresis under denaturing conditions, a critical reexamination. Biochemistry. 1977 Oct 18;16(21):4743–4751. doi: 10.1021/bi00640a033. [DOI] [PubMed] [Google Scholar]
  30. Livi G. P., Hicks J. B., Klar A. J. The sum1-1 mutation affects silent mating-type gene transcription in Saccharomyces cerevisiae. Mol Cell Biol. 1990 Jan;10(1):409–412. doi: 10.1128/mcb.10.1.409. [DOI] [PMC free article] [PubMed] [Google Scholar]
  31. Marshall M., Mahoney D., Rose A., Hicks J. B., Broach J. R. Functional domains of SIR4, a gene required for position effect regulation in Saccharomyces cerevisiae. Mol Cell Biol. 1987 Dec;7(12):4441–4452. doi: 10.1128/mcb.7.12.4441. [DOI] [PMC free article] [PubMed] [Google Scholar]
  32. Mullen J. R., Kayne P. S., Moerschell R. P., Tsunasawa S., Gribskov M., Colavito-Shepanski M., Grunstein M., Sherman F., Sternglanz R. Identification and characterization of genes and mutants for an N-terminal acetyltransferase from yeast. EMBO J. 1989 Jul;8(7):2067–2075. doi: 10.1002/j.1460-2075.1989.tb03615.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  33. Nasmyth K. A. Molecular genetics of yeast mating type. Annu Rev Genet. 1982;16:439–500. doi: 10.1146/annurev.ge.16.120182.002255. [DOI] [PubMed] [Google Scholar]
  34. Nasmyth K. A., Tatchell K., Hall B. D., Astell C., Smith M. A position effect in the control of transcription at yeast mating type loci. Nature. 1981 Jan 22;289(5795):244–250. doi: 10.1038/289244a0. [DOI] [PubMed] [Google Scholar]
  35. Nasmyth K. A. The regulation of yeast mating-type chromatin structure by SIR: an action at a distance affecting both transcription and transposition. Cell. 1982 Sep;30(2):567–578. doi: 10.1016/0092-8674(82)90253-7. [DOI] [PubMed] [Google Scholar]
  36. Nasmyth K., Shore D. Transcriptional regulation in the yeast life cycle. Science. 1987 Sep 4;237(4819):1162–1170. doi: 10.1126/science.3306917. [DOI] [PubMed] [Google Scholar]
  37. Rine J., Herskowitz I. Four genes responsible for a position effect on expression from HML and HMR in Saccharomyces cerevisiae. Genetics. 1987 May;116(1):9–22. doi: 10.1093/genetics/116.1.9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  38. Rine J., Strathern J. N., Hicks J. B., Herskowitz I. A suppressor of mating-type locus mutations in Saccharomyces cerevisiae: evidence for and identification of cryptic mating-type loci. Genetics. 1979 Dec;93(4):877–901. doi: 10.1093/genetics/93.4.877. [DOI] [PMC free article] [PubMed] [Google Scholar]
  39. Roman H., Sands S. M. Heterogeneity of Clones of Saccharomyces Derived from Haploid Ascospores. Proc Natl Acad Sci U S A. 1953 Mar;39(3):171–179. doi: 10.1073/pnas.39.3.171. [DOI] [PMC free article] [PubMed] [Google Scholar]
  40. Schnell R., Rine J. A position effect on the expression of a tRNA gene mediated by the SIR genes in Saccharomyces cerevisiae. Mol Cell Biol. 1986 Feb;6(2):494–501. doi: 10.1128/mcb.6.2.494. [DOI] [PMC free article] [PubMed] [Google Scholar]
  41. Shore D., Stillman D. J., Brand A. H., Nasmyth K. A. Identification of silencer binding proteins from yeast: possible roles in SIR control and DNA replication. EMBO J. 1987 Feb;6(2):461–467. doi: 10.1002/j.1460-2075.1987.tb04776.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
  42. Southern E. M. Detection of specific sequences among DNA fragments separated by gel electrophoresis. J Mol Biol. 1975 Nov 5;98(3):503–517. doi: 10.1016/s0022-2836(75)80083-0. [DOI] [PubMed] [Google Scholar]
  43. Strathern J. N., Klar A. J., Hicks J. B., Abraham J. A., Ivy J. M., Nasmyth K. A., McGill C. Homothallic switching of yeast mating type cassettes is initiated by a double-stranded cut in the MAT locus. Cell. 1982 Nov;31(1):183–192. doi: 10.1016/0092-8674(82)90418-4. [DOI] [PubMed] [Google Scholar]
  44. Strathern J., Hicks J., Herskowitz I. Control of cell type in yeast by the mating type locus. The alpha 1-alpha 2 hypothesis. J Mol Biol. 1981 Apr 15;147(3):357–372. doi: 10.1016/0022-2836(81)90488-5. [DOI] [PubMed] [Google Scholar]
  45. Strathern J., Shafer B., Hicks J., McGill C. a/Alpha-specific repression by MAT alpha 2. Genetics. 1988 Sep;120(1):75–81. doi: 10.1093/genetics/120.1.75. [DOI] [PMC free article] [PubMed] [Google Scholar]

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