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The yeast gene, MDM20, is necessary for mitochondrial inheritance and organization of the actin cytoskeleton.
- Source :
-
The Journal of cell biology [J Cell Biol] 1997 Apr 07; Vol. 137 (1), pp. 141-53. - Publication Year :
- 1997
-
Abstract
- In Saccharomyces cerevisiae, the growing bud inherits a portion of the mitochondrial network from the mother cell soon after it emerges. Although this polarized transport of mitochondria is thought to require functions of the cytoskeleton, there are conflicting reports concerning the nature of the cytoskeletal element involved. Here we report the isolation of a yeast mutant, mdm20, in which both mitochondrial inheritance and actin cables (bundles of actin filaments) are disrupted. The MDM20 gene encodes a 93-kD polypeptide with no homology to other characterized proteins. Extra copies of TPM1, a gene encoding the actin filament-binding protein tropomyosin, suppress mitochondrial inheritance defects and partially restore actin cables in mdm20 delta cells. Synthetic lethality is also observed between mdm20 and tpm1 mutant strains. Overexpression of a second yeast tropomyosin, Tpm2p, rescues mutant phenotypes in the mdm20 strain to a lesser extent. Together, these results provide compelling evidence that mitochondrial inheritance in yeast is an actin-mediated process. MDM20 and TPM1 also exhibit the same pattern of genetic interactions; mutations in MDM20 are synthetically lethal with mutations in BEM2 and MYO2 but not SAC6. Although MDM20 and TPM1 are both required for the formation and/or stabilization of actin cables, mutations in these genes disrupt mitochondrial inheritance and nuclear segregation to different extents. Thus, Mdm20p and Tpm1p may act in vivo to establish molecular and functional heterogeneity of the actin cytoskeleton.
- Subjects :
- Acetyltransferases
Amino Acid Sequence
Carrier Proteins genetics
Cell Division genetics
Cell Nucleus genetics
DNA, Mitochondrial analysis
GTPase-Activating Proteins
Gene Dosage
Genes, Fungal physiology
Genetic Complementation Test
Genetic Testing
Membrane Glycoproteins genetics
Molecular Sequence Data
Mutagenesis physiology
N-Terminal Acetyltransferase B
Phenotype
Proteins genetics
Rho Factor genetics
Saccharomyces cerevisiae chemistry
Saccharomyces cerevisiae cytology
Sequence Analysis, DNA
Temperature
Tropomyosin genetics
Tropomyosin metabolism
Actins metabolism
Cytoskeleton physiology
Fungal Proteins genetics
Microfilament Proteins
Mitochondria genetics
Myosin Heavy Chains
Myosin Type II
Myosin Type V
Saccharomyces cerevisiae genetics
Saccharomyces cerevisiae Proteins
Schizosaccharomyces pombe Proteins
Subjects
Details
- Language :
- English
- ISSN :
- 0021-9525
- Volume :
- 137
- Issue :
- 1
- Database :
- MEDLINE
- Journal :
- The Journal of cell biology
- Publication Type :
- Academic Journal
- Accession number :
- 9105043
- Full Text :
- https://doi.org/10.1083/jcb.137.1.141