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Pheromone-regulated genes required for yeast mating differentiation.

Erdman S, Lin L, Malczynski M, Snyder M - J. Cell Biol. (1998)

Bottom Line: Transposon insertion alleles corresponding to 20 genes that are novel or had not previously been known to be pheromone regulated were examined for effects on the mating process.Mutations in four novel genes, FIG1, FIG2, KAR5/ FIG3, and FIG4 were found to cause mating defects.Our results indicate that a variety of novel genes are expressed specifically during mating differentiation to mediate proper cell morphogenesis, cell fusion, and other steps of the mating process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Yale University, New Haven, Connecticut 06520-8103, USA.

ABSTRACT
Yeast cells mate by an inducible pathway that involves agglutination, mating projection formation, cell fusion, and nuclear fusion. To obtain insight into the mating differentiation of Saccharomyces cerevisiae, we carried out a large-scale transposon tagging screen to identify genes whose expression is regulated by mating pheromone. 91,200 transformants containing random lacZ insertions were screened for beta-galactosidase (beta-gal) expression in the presence and absence of alpha factor, and 189 strains containing pheromone-regulated lacZ insertions were identified. Transposon insertion alleles corresponding to 20 genes that are novel or had not previously been known to be pheromone regulated were examined for effects on the mating process. Mutations in four novel genes, FIG1, FIG2, KAR5/ FIG3, and FIG4 were found to cause mating defects. Three of the proteins encoded by these genes, Fig1p, Fig2p, and Fig4p, are dispensible for cell polarization in uniform concentrations of mating pheromone, but are required for normal cell polarization in mating mixtures, conditions that involve cell-cell communication. Fig1p and Fig2p are also important for cell fusion and conjugation bridge shape, respectively. The fourth protein, Kar5p/Fig3p, is required for nuclear fusion. Fig1p and Fig2p are likely to act at the cell surface as Fig1:: beta-gal and Fig2::beta-gal fusion proteins localize to the periphery of mating cells. Fig4p is a member of a family of eukaryotic proteins that contain a domain homologous to the yeast Sac1p. Our results indicate that a variety of novel genes are expressed specifically during mating differentiation to mediate proper cell morphogenesis, cell fusion, and other steps of the mating process.

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(A) Predicted structural features of the Fig1, Fig2,  Kar5/Fig3, and Fig4 proteins. Putative transmembrane domains  (TMDs) are indicated by vertical wavy lines. Potential N-linked  glycosylation sites are indicated by circles. These occur within a  predicted extracellular loop between TMD1 and TMD2 of Fig1p  and in the Ser/Thr rich region of Fig2p. The predicted signal peptide (SP) and GPI anchor of Fig2p are indicated. The putative  coiled-coil regions of Kar5/Fig3p are depicted by wavy horizontal  lines. The Sac1p homology domain of Fig4p is indicated by a  striped region. (B) Alignments of protein sequences corresponding to the Sac1p homology domain present in family members  displaying highest similarity to Fig4p with Sac1p. Identities and  conservative sequence changes are boxed.
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Figure 11: (A) Predicted structural features of the Fig1, Fig2, Kar5/Fig3, and Fig4 proteins. Putative transmembrane domains (TMDs) are indicated by vertical wavy lines. Potential N-linked glycosylation sites are indicated by circles. These occur within a predicted extracellular loop between TMD1 and TMD2 of Fig1p and in the Ser/Thr rich region of Fig2p. The predicted signal peptide (SP) and GPI anchor of Fig2p are indicated. The putative coiled-coil regions of Kar5/Fig3p are depicted by wavy horizontal lines. The Sac1p homology domain of Fig4p is indicated by a striped region. (B) Alignments of protein sequences corresponding to the Sac1p homology domain present in family members displaying highest similarity to Fig4p with Sac1p. Identities and conservative sequence changes are boxed.

Mentions: The four genes characterized in detail in this study, FIG1, FIG2, KAR5/FIG3, and FIG4, are predicted to encode proteins of 298-, 1609-, 504-, and 879-amino acids, respectively. Each of these proteins is predicted to contain domains suggestive of a structure, localization, or function of the proteins. (Fig. 11 A).


Pheromone-regulated genes required for yeast mating differentiation.

Erdman S, Lin L, Malczynski M, Snyder M - J. Cell Biol. (1998)

(A) Predicted structural features of the Fig1, Fig2,  Kar5/Fig3, and Fig4 proteins. Putative transmembrane domains  (TMDs) are indicated by vertical wavy lines. Potential N-linked  glycosylation sites are indicated by circles. These occur within a  predicted extracellular loop between TMD1 and TMD2 of Fig1p  and in the Ser/Thr rich region of Fig2p. The predicted signal peptide (SP) and GPI anchor of Fig2p are indicated. The putative  coiled-coil regions of Kar5/Fig3p are depicted by wavy horizontal  lines. The Sac1p homology domain of Fig4p is indicated by a  striped region. (B) Alignments of protein sequences corresponding to the Sac1p homology domain present in family members  displaying highest similarity to Fig4p with Sac1p. Identities and  conservative sequence changes are boxed.
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2140177&req=5

Figure 11: (A) Predicted structural features of the Fig1, Fig2, Kar5/Fig3, and Fig4 proteins. Putative transmembrane domains (TMDs) are indicated by vertical wavy lines. Potential N-linked glycosylation sites are indicated by circles. These occur within a predicted extracellular loop between TMD1 and TMD2 of Fig1p and in the Ser/Thr rich region of Fig2p. The predicted signal peptide (SP) and GPI anchor of Fig2p are indicated. The putative coiled-coil regions of Kar5/Fig3p are depicted by wavy horizontal lines. The Sac1p homology domain of Fig4p is indicated by a striped region. (B) Alignments of protein sequences corresponding to the Sac1p homology domain present in family members displaying highest similarity to Fig4p with Sac1p. Identities and conservative sequence changes are boxed.
Mentions: The four genes characterized in detail in this study, FIG1, FIG2, KAR5/FIG3, and FIG4, are predicted to encode proteins of 298-, 1609-, 504-, and 879-amino acids, respectively. Each of these proteins is predicted to contain domains suggestive of a structure, localization, or function of the proteins. (Fig. 11 A).

Bottom Line: Transposon insertion alleles corresponding to 20 genes that are novel or had not previously been known to be pheromone regulated were examined for effects on the mating process.Mutations in four novel genes, FIG1, FIG2, KAR5/ FIG3, and FIG4 were found to cause mating defects.Our results indicate that a variety of novel genes are expressed specifically during mating differentiation to mediate proper cell morphogenesis, cell fusion, and other steps of the mating process.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Yale University, New Haven, Connecticut 06520-8103, USA.

ABSTRACT
Yeast cells mate by an inducible pathway that involves agglutination, mating projection formation, cell fusion, and nuclear fusion. To obtain insight into the mating differentiation of Saccharomyces cerevisiae, we carried out a large-scale transposon tagging screen to identify genes whose expression is regulated by mating pheromone. 91,200 transformants containing random lacZ insertions were screened for beta-galactosidase (beta-gal) expression in the presence and absence of alpha factor, and 189 strains containing pheromone-regulated lacZ insertions were identified. Transposon insertion alleles corresponding to 20 genes that are novel or had not previously been known to be pheromone regulated were examined for effects on the mating process. Mutations in four novel genes, FIG1, FIG2, KAR5/ FIG3, and FIG4 were found to cause mating defects. Three of the proteins encoded by these genes, Fig1p, Fig2p, and Fig4p, are dispensible for cell polarization in uniform concentrations of mating pheromone, but are required for normal cell polarization in mating mixtures, conditions that involve cell-cell communication. Fig1p and Fig2p are also important for cell fusion and conjugation bridge shape, respectively. The fourth protein, Kar5p/Fig3p, is required for nuclear fusion. Fig1p and Fig2p are likely to act at the cell surface as Fig1:: beta-gal and Fig2::beta-gal fusion proteins localize to the periphery of mating cells. Fig4p is a member of a family of eukaryotic proteins that contain a domain homologous to the yeast Sac1p. Our results indicate that a variety of novel genes are expressed specifically during mating differentiation to mediate proper cell morphogenesis, cell fusion, and other steps of the mating process.

Show MeSH
Related in: MedlinePlus