Consequences of a deletion in dspA on transcript accumulation in Synechocystis sp. strain PCC6803.
A sensor histidine kinase of Synechococcus sp. strain PCC7942, designated nblS, was previously identified and shown to be critical for the acclimation of cells to high-light and nutrient limitation conditions and to influence the expression of a number of light-responsive genes. The nblS orthologue in Synechocystis sp. strain PCC6803 is designated dspA (also called hik33). We have generated a dspA null mutant and analyzed global gene expression in both the mutant and wild-type strains under high- and low-light conditions. The mutant is aberrant for the expression of many genes encoding proteins critical for photosynthesis, phosphate and carbon acquisition, and the amelioration of stress conditions. Furthermore, transcripts from a number of genes normally detected only during exposure of wild-type cells to high-light conditions become partially constitutive in the low-light-grown dspA mutant. Other genes for which transcripts decline upon exposure of wild-type cells to high light are already lower in the mutant during growth in low light. These results suggest that DspA may influence gene expression in both a positive and a negative manner and that the dspA mutant behaves as if it were experiencing stress conditions (e.g., high-light exposure) even when maintained at near-optimal growth conditions for wild-type cells. This is discussed with respect to the importance of DspA for regulating the responses of the cell to environmental cues.
Tu
Chao-Jung
CJ
Department of Plant Biology, The Carnegie Institution of Washington, 260 Panama St., Stanford, CA 94305, USA. cjtu@stanford.edu
Shrager
Jeffrey
J
Burnap
Robert L
RL
Postier
Bradley L
BL
Grossman
Arthur R
AR
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D000458:Cyanobacteria / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D017353:Gene Deletion; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D000071677:Histidine Kinase; D008027:Light; D020411:Oligonucleotide Array Sequence Analysis; D010788:Photosynthesis; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D014158:Transcription, Genetic
D001426:Bacterial Proteins; D011494:Protein Kinases; D000071677:Histidine Kinase