TY - JOUR

T1 - Characterization of fus1 of Schizosaccharomyces pombe: a developmentally controlled function needed for conjugation

AU - Petersen, J

AU - Weilguny, D

AU - Egel, R

AU - Nielsen, O

AU - Nielsen, Olaf

PY - 1995/7/1

Y1 - 1995/7/1

N2 - In Schizosaccharomyces pombe, the fus1 mutation blocks conjugation at a point after cell contact and agglutination. The cell walls separating the mating partners are not degraded, which prevents cytoplasmic fusion. In order to investigate the molecular mechanism of conjugation, we cloned the fus1 gene and found that it is capable of encoding a 1,372-amino-acid protein with no significant similarities to other known proteins. Expression of the fus1 gene is regulated by the developmental state of the cells. Transcription is induced by nitrogen starvation and requires a pheromone signal in both P and M cell types. Consequently, mutants defective in the pheromone response pathway fail to induce fus1 expression. The ste11 gene, which encodes a transcription factor controlling expression of many genes involved in sexual differentiation, is also required for transcription of fus1. Furthermore, deletion of two potential Ste11 recognition sites in the fus1 promoter region abolished transcription, and expression could be restored when we inserted a different Ste11 site from the mat1-P promoter. Since this element was inverted relative to the fus1 element, we conclude that activation of transcription by Ste11 is independent of orientation. Although the fus1 mutant has a phenotype very similar to that of Saccharomyces cerevisiae fus1 mutants, the two proteins appear to have different roles in the process of cell fusion. Budding yeast Fus1 is a typical membrane protein and contains an SH3 domain. Fission yeast Fus1 has no features of a membrane protein, yet it appears to localize to the projection tip. A characteristic proline-rich potential SH3 binding site may mediate interaction with other proteins.

AB - In Schizosaccharomyces pombe, the fus1 mutation blocks conjugation at a point after cell contact and agglutination. The cell walls separating the mating partners are not degraded, which prevents cytoplasmic fusion. In order to investigate the molecular mechanism of conjugation, we cloned the fus1 gene and found that it is capable of encoding a 1,372-amino-acid protein with no significant similarities to other known proteins. Expression of the fus1 gene is regulated by the developmental state of the cells. Transcription is induced by nitrogen starvation and requires a pheromone signal in both P and M cell types. Consequently, mutants defective in the pheromone response pathway fail to induce fus1 expression. The ste11 gene, which encodes a transcription factor controlling expression of many genes involved in sexual differentiation, is also required for transcription of fus1. Furthermore, deletion of two potential Ste11 recognition sites in the fus1 promoter region abolished transcription, and expression could be restored when we inserted a different Ste11 site from the mat1-P promoter. Since this element was inverted relative to the fus1 element, we conclude that activation of transcription by Ste11 is independent of orientation. Although the fus1 mutant has a phenotype very similar to that of Saccharomyces cerevisiae fus1 mutants, the two proteins appear to have different roles in the process of cell fusion. Budding yeast Fus1 is a typical membrane protein and contains an SH3 domain. Fission yeast Fus1 has no features of a membrane protein, yet it appears to localize to the projection tip. A characteristic proline-rich potential SH3 binding site may mediate interaction with other proteins.

KW - Amino Acid Sequence

KW - Base Sequence

KW - Blotting, Northern

KW - Blotting, Western

KW - Cloning, Molecular

KW - Conjugation, Genetic

KW - DNA Mutational Analysis

KW - Fluorescent Antibody Technique

KW - Fungal Proteins

KW - Gene Expression Regulation, Fungal

KW - Genes, Fungal

KW - Genes, src

KW - Genetic Complementation Test

KW - Membrane Proteins

KW - Molecular Sequence Data

KW - Mutation

KW - Pheromones

KW - Promoter Regions, Genetic

KW - Restriction Mapping

KW - Saccharomyces cerevisiae Proteins

KW - Schizosaccharomyces

KW - Schizosaccharomyces pombe Proteins

KW - Sequence Analysis, DNA

KW - Sequence Deletion

KW - Sequence Homology, Amino Acid

KW - Signal Transduction

KW - Transcription Factors

KW - Transcription, Genetic

M3 - Journal article

C2 - 7791776

VL - 15

SP - 3697

EP - 3707

JO - Molecular and Cellular Biology

JF - Molecular and Cellular Biology

SN - 0270-7306

IS - 7

ER -