Disruption of the single tropomyosin gene in yeast results in the disappearance of actin cables from the cytoskeleton.
The yeast tropomyosin gene, designated TPM1, is present in a single copy per haploid genome and encodes a protein with a predicted molecular weight of 23.5 kd. The protein sequence is homologous to higher cell tropomyosins, including the characteristic hydrophobic-hydrophilic pseudoheptapeptide repeats. Indirect immunofluorescence microscopy reveals that tropomyosin is localized with actin cables in wild-type cells. Disruption of TPM1 is not lethal, but results in a reduced growth rate and disappearance of actin cables. Strains carrying the conditional actin mutation act1-2 also lack actin cables; overexpression of tropomyosin in these strains partially restores actin cables. These results strongly suggest that tropomyosin interacts with F actin in vivo and may play an important role in assembling or stabilizing actin cables in yeast.
Liu
H P
HP
Section on Biochemistry Molecular, Cornell University, Ithaca, New York 14853.
Bretscher
A
A
D000199:Actins / Q000378:metabolism*; D001483:Base Sequence; D003599:Cytoskeleton / Q000032:analysis / Q000378:metabolism*; D005786:Gene Expression Regulation; D005796:Genes; D005804:Genes, Lethal; D008969:Molecular Sequence Data; D012441:Saccharomyces cerevisiae; D014335:Tropomyosin / Q000032:analysis / Q000235:genetics*
D000199:Actins; D014335:Tropomyosin