The yeast SIS1 protein, a DnaJ homolog, is required for the initiation of translation

Zhong, T., Arndt, K. T. (June 1993) The yeast SIS1 protein, a DnaJ homolog, is required for the initiation of translation. Cell, 73 (6). pp. 1175-86. ISSN 0092-8674 (Print)

DOI: 10.1016/0092-8674(93)90646-8


The S. cerevisiae SIS1 gene is essential and encodes a heat shock protein with similarity to the bacterial DnaJ protein. At the nonpermissive temperature, temperature-sensitive sis1 strains rapidly accumulate 80S ribosomes and have decreased amounts of polysomes. Certain alterations in 60S ribosomal subunits can suppress the temperature-sensitive phenotype of sis1 strains and prevent the accumulation of 80S ribosomes and the loss of polysomes normally seen under conditions of reduced SIS1 function. Analysis of sucrose gradients for SIS1 protein shows that a large fraction of SIS1 is associated with 40S ribosomal subunits and the smaller polysomes. These and other results indicate that SIS1 is required for the normal initiation of translation. Because DnaJ has been shown to mediate the dissociation of several protein complexes, the requirement of SIS1 in the initiation of translation might be for mediating the dissociation of a specific protein complex of the translation machinery.

Item Type: Paper
Uncontrolled Keywords: Amino Acid Sequence Base Sequence DNA Mutational Analysis Fungal Proteins/chemistry/ genetics/ metabolism Heat-Shock Proteins/metabolism Molecular Sequence Data Protein Biosynthesis Research Support, U.S. Gov't, P.H.S. Ribosomal Proteins/metabolism Saccharomyces cerevisiae/ genetics Saccharomyces cerevisiae Proteins Sequence Homology, Amino Acid Sequence Homology, Nucleic Acid
Subjects: organs, tissues, organelles, cell types and functions > organelles, types and functions > ribosome
bioinformatics > genomics and proteomics > genetics & nucleic acid processing > DNA, RNA structure, function, modification > translation
organism description > yeast
CSHL Authors:
Communities: CSHL labs
Depositing User: Matt Covey
Date: 18 June 1993
Date Deposited: 21 Apr 2016 16:09
Last Modified: 21 Apr 2016 16:09
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