The spectrum of spontaneous mutations caused by deficiency in proteasome maturase Ump1 in Saccharomyces cerevisiae.
Ump1 is responsible for maturation of the catalytic core of the 26S proteasome. Dysfunction of Ump1 causes an increase in the frequency of spontaneous mutations in Saccharomyces cerevisiae. In this study we analyze the spectrum of mutations occurring spontaneously in yeast deficient in Ump1 by use of the SUP4-o system. Single base substitutions predominate among the mutations analyzed (73 of the 91 alterations examined). Two major classes are GC to TA transversions and GC to AT transitions ( approximately 50 and approximately 30% of base substitutions, respectively). Besides base substitutions, almost all the major types of sequence alterations are represented. The specificity and distribution of mutations occurring in the ump1 strain are unique compared to the spectra previously established for other yeast mutators. However, the profile of mutations arising in this strain is similar to that observed in wild type. The same similarity has previously been reported for yeast deficient in Mms2, a protein involved in Rad6-dependent postreplication DNA repair (PRR). The specificity of the mutator effect caused by ump1 is discussed in light of the proposed role of the proteasome activity in the regulation of the PRR mechanisms.
McIntyre
Justyna
J
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, ul. Pawinskiego 5A, 02-106, Warsaw, Poland.
Baranowska
Hanna
H
Skoneczna
Adrianna
A
Halas
Agnieszka
A
Sledziewska-Gojska
Ewa
E
D002384:Catalysis; D005800:Genes, Fungal / Q000502:physiology; D018832:Molecular Chaperones / Q000235:genetics* / Q000502:physiology; D016296:Mutagenesis; D009154:Mutation; D017354:Point Mutation; D046988:Proteasome Endopeptidase Complex / Q000096:biosynthesis / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000502:physiology
D018832:Molecular Chaperones; D029701:Saccharomyces cerevisiae Proteins; C110856:proteasome maturation protein; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease