The iscS gene deficiency affects the expression of pyrimidine metabolism genes.
Inactivation of iscS encoding cysteine desulfurase results in a slow growth phenotype associated with the deficiency of iron-sulfur clusters, thiamine, NAD, and tRNA thionucleosides in Escherichia coli. However, the other roles of iscSin vivo are unknown. By using differential screening strategies, we identified 2 pyrimidine salvage enzymes, namely, uridine phosphorylase and cytidine deaminase, which were down-regulated in the iscS mutant. Both enzymes are positively regulated by the cAMP receptor protein (CRP). We also identified a novel protein complex, namely, YeiT-YeiA, whose expression level was decreased in the iscS mutant. The recombinant YeiT-YeiA complex exhibited NADH-dependent dihydropyrimidine dehydrogenase activity, indicating its role in pyrimidine metabolism. The presence of a CRP-binding consensus sequence on the 5'-upstream of the yeiT-YeiA gene suggests its regulation by CRP. These results provide a clue to the possible role of iscS in pyrimidine metabolism by gene regulation.
Mihara
Hisaaki
H
Institute for Chemical Research, Kyoto University, Gokasho, Uji, Kyoto 611-0011, Japan. mihara@mbc.kuicr.kyoto-u.ac.jp
Hidese
Ryota
R
Yamane
Masahiro
M
Kurihara
Tatsuo
T
Esaki
Nobuyoshi
N
D001483:Base Sequence; D013437:Carbon-Sulfur Lyases / Q000235:genetics / Q000502:physiology*; D016384:Consensus Sequence; D002373:Cyclic AMP Receptor Protein / Q000378:metabolism; D003564:Cytidine Deaminase / Q000235:genetics / Q000378:metabolism; D050744:Dihydrouracil Dehydrogenase (NAD+) / Q000235:genetics / Q000378:metabolism; D042943:Dihydrouracil Dehydrogenase (NADP) / Q000378:metabolism; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D011743:Pyrimidines / Q000378:metabolism*; D014157:Transcription Factors / Q000378:metabolism; D014543:Uridine Phosphorylase / Q000235:genetics / Q000378:metabolism
D002373:Cyclic AMP Receptor Protein; D029968:Escherichia coli Proteins; D011743:Pyrimidines; D014157:Transcription Factors; C481662:crp protein, E coli; D050744:Dihydrouracil Dehydrogenase (NAD+); D042943:Dihydrouracil Dehydrogenase (NADP); D014543:Uridine Phosphorylase; D003564:Cytidine Deaminase; D013437:Carbon-Sulfur Lyases; C080546:cysteine desulfurase; C030986:pyrimidine