Dual role for the yeast THI4 gene in thiamine biosynthesis and DNA damage tolerance
The THI4 gene of Saccharomyces cerevisiae encodes an enzyme of the thiamine biosynthetic pathway. The plant homolog thi1, from Arabidopsis thaliana, is also involved in thiamine biosynthesis; but was originally cloned due to its capacity to complement DNA repair deficient phenotypes in Escherichia c...
Saved in:
Published in | Journal of molecular biology Vol. 273; no. 1; pp. 114 - 121 |
---|---|
Main Authors | , , , , , , |
Format | Journal Article |
Language | English |
Published |
England
Elsevier Ltd
17.10.1997
|
Subjects | |
Online Access | Get full text |
Cover
Loading…
Summary: | The
THI4 gene of
Saccharomyces cerevisiae encodes an enzyme of the thiamine biosynthetic pathway. The plant homolog
thi1, from
Arabidopsis thaliana, is also involved in thiamine biosynthesis; but was originally cloned due to its capacity to complement DNA repair deficient phenotypes in
Escherichia coli. Here, the behavior of a
thi4 disrupted strain was examined for increased sensitivity to treatment with the DNA damaging agents ultraviolet radiation (UV, 254 nm) and methyl methanesulfonate (MMS). Although the
thi4 null mutant showed a similar level of survival as the wild-type strain, a higher frequency of respiratory mutants was induced by the two treatments. A similar phenotype was seen with wild-type strains expressing an antisense
THI4 construct. Further analysis of respiratory mutants revealed that these were due to mutations of mitochondrial DNA (mtDNA) rather than nuclear DNA, consisting of ρ
− petite mutants. Moreover, the frequency of mutations was unaffected by the presence or absence of thiamine in the growth medium, and the defect leading to induction of petites in the
thi4 mutant was corrected by expression of the
Arabidopsis thi1 gene. Thus, Thi4 and its plant homolog appear to be dual functional proteins with roles in thiamine biosynthesis and mitochondrial DNA damage tolerance. |
---|---|
Bibliography: | ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0022-2836 1089-8638 |
DOI: | 10.1006/jmbi.1997.1302 |