DNA microarray comparisons of plant factor- and nitrogen deprivation-induced Hormogonia reveal decision-making transcriptional regulation patterns in Nostoc punctiforme.
Hormogonia are nongrowing filaments, motile by means of a gliding mechanism, that are produced by certain cyanobacteria. Their differentiation is induced by positive and negative factors for growth, such as deprivation of combined nitrogen (nitrogen stress induction [NSI]). In Nostoc punctiforme, they are also induced by the exudate (hormogonium-inducing factor [HIF]) of a symbiotic plant partner. Time course (0.5 to 24 h) transcription profiles were determined by DNA microarray assays for hormogonia of N. punctiforme following induction by HIF and NSI. Clustering analysis revealed both common and distinct transcriptional patterns for the two methods of induction. By 24 h, a common set of 1,328 genes was identified. This 24-h common set of genes arose by the transition of 474 genes from an 819-member common set of genes at 1 h after induction; 405 and 51 genes unique to the HIF and NSI groups at 1 h, respectively; and 398 genes differentially transcribed at later time points. The NSI hormogonia showed a transcriptional checkpoint at 12 h following induction in which up- and downregulated genes were transiently down- or upregulated, respectively. The transient changes in these 1,043 genes appeared to reflect a switch back to a vegetative growth state. Such a checkpoint was not seen in HIF hormogonia. Genes uniquely upregulated in HIF hormogonia included those encoding proteins hypothesized to synthesize a metabolite repressor of hormogonium differentiation. Approximately 34 to 42% of the 6,893 printed genes were differentially transcribed during hormogonium differentiation; about half of those genes were upregulated, and 1,034 genes responded within 0.5 h after induction. These collective results indicate extensive and rapid global changes in the transcription of specific genes during the differentiation of these specialized filaments.
Campbell
Elsie L
EL
Department of Microbiology, One Shields Ave., University of California, Davis, CA 95616, USA.
Christman
Harry
H
Meeks
John C
JC
D001426:Bacterial Proteins / Q000235:genetics; D015152:Blotting, Northern; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D008954:Models, Biological; D009584:Nitrogen / Q000378:metabolism* / Q000494:pharmacology; D046937:Nostoc / Q000235:genetics*; D020411:Oligonucleotide Array Sequence Analysis / Q000379:methods; D010944:Plants / Q000382:microbiology*; D013559:Symbiosis / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
D001426:Bacterial Proteins; D009584:Nitrogen
Arch Microbiol. 2002 Dec;178(6):395-403
12420158
Mol Microbiol. 2003 Mar;47(5):1239-49
12603731
J Bacteriol. 1995 Nov;177(21):6184-94
7592384
J Bacteriol. 2005 Feb;187(3):1074-90
15659685
Appl Environ Microbiol. 1989 Jan;55(1):125-31
16347816
Bioinformatics. 2002 Jan;18(1):207-8
11836235
Planta. 1983 Jun;158(2):157-65
24264545
J Bacteriol. 1987 Jan;169(1):218-23
3098731
Mol Plant Microbe Interact. 1997 Mar;10(2):280-9
9057333
Plant Cell. 1991 Feb;3(2):191-201
12324595
J Bacteriol. 2007 Jul;189(14):5247-56
17483217
Microbiol Mol Biol Rev. 2002 Mar;66(1):94-121; table of contents
11875129
Photosynth Res. 2001;70(1):85-106
16228364
Mol Microbiol. 2003 Jan;47(2):573-82
12519206
J Bacteriol. 2007 Jun;189(12):4547-51
17416648
Curr Biol. 1998 Oct 22;8(21):1161-8
9799733
Plant Physiol. 1955 Jul;30(4):366-72
16654787