This Article Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Brenner, M. Articles by Singer, M. Search for Related Content PubMed PubMed Citation Articles by Brenner, M. Articles by Singer, M.

nsd, a Locus That Affects the Myxococcus xanthus Cellular Response to Nutrient Concentration

Margaret Brenner, Anthony G. Garza, and Mitchell Singer^*

Section of Microbiology and Center for Genetics and Development, The University of California, Davis, Davis, California 95616

Received 5 December 2003/ Accepted 20 February 2004

Expression of the previously reported Tn5lac 4469 insertion in Myxococcus xanthus cells is regulated by the starvation response. Interested in learning more about the starvation response, we cloned and sequenced the region containing the insertion. Our analysis shows that the gene fusion is located in an open reading frame that we have designated nsd (nutrient sensing/utilizing defective) and that its expression is driven by a ⁷⁰-like promoter. Sequence analysis of the nsd gene product provides no information on the potential structure or function of the encoded protein. In a further effort to learn about the role of nsd in the starvation response, we closely examined the phenotype of cells carrying the nsd::Tn5lac 4469 mutation. Our analysis showed that these cells initiate development on medium that contains nutrients sufficient to sustain vegetative growth of wild-type cells. Furthermore, in liquid media these same nutrient concentrations elicit a severe impairment of growth of nsd cells. The data suggest that the nsd cells launch a starvation response when there are enough nutrients to prevent one. In support of this hypothesis, we found that, when grown in these nutrient concentrations, nsd cells accumulate guanosine tetraphosphate, the cellular starvation signal. Therefore, we propose that nsd is used by cells to respond to available nutrient levels.

Present address: School of Molecular Biosciences, Washington State University, Pullman, Wash.