| Autor: |
Eisinger DP; Department of Biochemistry, Dartmouth Medical School, Hanover, New Hampshire 03755, USA., Dick FA, Trumpower BL |
| Jazyk: |
angličtina |
| Zdroj: |
Molecular and cellular biology [Mol Cell Biol] 1997 Sep; Vol. 17 (9), pp. 5136-45. |
| DOI: |
10.1128/MCB.17.9.5136 |
| Abstrakt: |
QSR1 is a recently discovered, essential Saccharomyces cerevisiae gene, which encodes a 60S ribosomal subunit protein. Thirty-one unique temperature-sensitive alleles of QSR1 were generated by regional codon randomization within a conserved 20-amino-acid sequence of the QSR1-encoded protein. The temperature-sensitive mutants arrest as viable, large, unbudded cells 24 to 48 h after a shift to 37 degrees C. Polysome and ribosomal subunit analysis by velocity gradient centrifugation of lysates from temperature-sensitive qsr1 mutants and from cells in which Qsr1p was depleted by down regulation of an inducible promoter revealed the presence of half-mer polysomes and a large pool of free 60S subunits that lack Qsr1p. In vitro subunit-joining assays and analysis of a mutant conditional for the synthesis of Qsr1p demonstrate that 60S subunits devoid of Qsr1p are unable to join with 40S subunits whereas 60S subunits that contain either wild-type or mutant forms of the protein are capable of subunit joining. The defective 60S subunits result from a reduced association of mutant Qsr1p with 60S subunits. These results indicate that Qsr1p is required for ribosomal subunit joining. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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