Two regulatory networks mediated by light and glucose involved in glycolytic gene expression in cyanobacteria.
Fructose 1,6-bisphosphate aldolase (FBA) is an enzyme involved in both glycolytic and photosynthetic reactions in photosynthetic organisms. In prokaryotes, the bidirectional reaction proceeds in the same cellular compartment, i.e. the cytoplasm. Expression of the FBA gene, fbaA, is induced through two independent pathways, stimulated by continuous light and by glucose plus pulsed light (GPL), in a cyanobactrium, Synechocystis sp. PCC 6803. Under GPL conditions, glucose can be replaced by glucose analogs that are not even metabolized in a cell. Analyses of transcripts in deletion mutants suggested that both a histidine kinase, Hik8, and a response regulator, Sll1330, played important roles as signal components in fbaA expression under GPL conditions, but not under photosynthetic conditions. Analysis of a transformant in which sll1330 expression was enhanced demonstrated that fbaA expression was induced at least partially even without glucose, but for its further induction a pulsed light stimulus was required. These results substantiated that there are two light-dependent regulatory pathways for aldolase gene expression in this cyanobacterium.
School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, Hachioji, Tokyo, 192-0392 Japan.
Yosuke
Y
Tabei
Katsuhiko
K
Okada
Eisuke
E
Horii
Mayuka
M
Mitsui
Yoshiaki
Y
Nagashima
Tsutomu
T
Sakai
Takuya
T
Yoshida
Akio
A
Kamiya
Shoko
S
Fujiwara
Mikio
M
Tsuzuki
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D005634:Fructose-Bisphosphate Aldolase / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D053263:Gene Regulatory Networks; D005947:Glucose / Q000378:metabolism*; D000071677:Histidine Kinase; D008027:Light; D009154:Mutation; D010788:Photosynthesis / Q000235:genetics; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction; D046939:Synechocystis / Q000235:genetics* / Q000378:metabolism*
D001426:Bacterial Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase; D005634:Fructose-Bisphosphate Aldolase; D005947:Glucose