Lee R. Kroos
Professor
Associate Chair

B.S. 1981, Bowling Green State University
Ph.D. 1986, Stanford University
NSF Predoctoral Fellow, 1981-84, Stanford University
Helen Hay Whitney Postdoctoral Fellow, 1986-88, Harvard University

kroos@msu.edu
422 Biochemistry Building
Michigan State University
East Lansing, MI 48824-1319
Office: 517-355-9726
Lab: 517-353-0809
FAX: 517-353-9334

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Lee Kroos

Research Interests

Certain bacteria undergo developmental processes that include cell fate determination, cell to cell signaling, morphogenesis, and cellular differentiation. We exploit the biochemical and genetic simplicity of bacteria to explore the molecular mechanisms of gene regulation and protein function during development. The novel mechanisms we discover are likely to be used by many other microorganisms of medical, agricultural, and environmental importance.

Bacillus subtilis is a soil bacterium that undergoes development when starved. The cell is partitioned into two compartments, the mother cell and the forespore, each of which expresses distinct sets of genes in an ordered temporal fashion, under the control of different sigma subunits of RNA polymerase (Fig. 1).

We are investigating the regulation of genes that are expressed in the mother cell compartment during the later stages of sporulation under the control of s^K RNA polymerase. We have shown that s^K is first made as an inactive precursor (pro-s^K) and that processing to the active form in the mother cell depends on a signal from the forespore. Our current model for this novel type of signal transduction pathway is shown in (Fig. 2). MORE

Recent Publications

Daisuke I, Zhou R, Feig M, Kroos L. Evidence that the Bacillus subtilis SpoIIGA protein is a novel type of signal-transducing aspartic protease. J. Biol. Chem, March 31, 2008. Epub ahead of print. Link to publication

Kroos L. The Bacillus and Myxococcus developmental networks and their transcriptional regulators. Annu Rev Genet. 2007;41:13-39.

Wang L, Perpich J, Driks A, Kroos L. 2007. Maintaining the transcription factor SpoIIID level late during sporulation causes spore defects in Bacillus subtilis. J Bacteriol. 189(20):7302-9.

Wang L, Perpich J, Driks A, Kroos L. 2007. One perturbation of the mother cell gene regulatory network suppresses the effects of another during sporulation of Bacillus subtilis. J Bacteriol. 189(23):8467-73.

Viswanathan P, Ueki T, Inouye S, Kroos L. 2007. Combinatorial regulation of genes essential for Myxococcus xanthus development involves a response regulator and a LysR-type regulator. Proc Natl Acad Sci U S A. 8;104(19):7969-74.

Viswanathan P, Murphy K, Julien B, Garza AG, Kroos L. 2007. Regulation of dev, an Operon That Includes Genes Essential for Myxococcus xanthus Development and CRISPR-Associated Genes and Repeats. J Bacteriol. 189(10):3738-50.

Viswanathan, K., P. Viswanathan, and L. Kroos. 2006. Mutational analysis of the Myxococcus xanthus W4406 promoter region reveals an upstream negative regulatory element that mediates C-signal dependence. J. Bacteriol. 188:515-524.

Viswanathan, P., M. Singer, Kroos, L. 2006. Role of sD in regulating genes and signals during Myxococcus xanthus development. J. Bacteriol. 188:3246-3256.

Yoder-Himes, D.R. , Kroos, L. 2006. Regulation of the Myxococcus xanthus C-signal-dependent W4400 promoter by the essential developmental protein FruA. J. Bacteriol. 188:5167-5176.

Zhou R, Kroos L. 2005. Serine proteases from two cell types target different components of a complex that governs regulated intramembrane proteolysis of pro-sigmaK during Bacillus subtilis development. Mol Microbiol. 58(3):835-46.

Loconto J, Viswanathan P, Nowak SJ, Gloudemans M, Kroos L. 2005. Identification of the omega4406 regulatory region, a developmental promoter of Myxococcus xanthus, and a DNA segment responsible for chromosomal position-dependent inhibition of gene expression. J Bacteriol. 187(12):4149-62.

Kroos L. 2005. Eukaryotic-like signaling and gene regulation in a prokaryote that undergoes multicellular development. Proc Natl Acad Sci U S A. 102(8):2681-2. Epub 2005 Feb 14.

Prince H, Zhou R, Kroos L. 2005. Substrate requirements for regulated intramembrane proteolysis of Bacillus subtilis pro-sigmaK. J Bacteriol. 187(3):961-71.

Srinivasan D, Kroos L. 2004. Mutational analysis of the fruA promoter region demonstrates that C-Box and 5-base-pair elements are important for expression of an essential developmental gene of Myxococcus xanthus. J Bacteriol. 186(17):5961-7.

Yoder DR, Kroos L. 2004. Mutational analysis of the Myxococcus xanthus Omicron4499 promoter region reveals shared and unique properties in comparison with other C-signal-dependent promoters. J Bacteriol. 186(12):3766-76.

Zhou R, Kroos L. 2004. BofA protein inhibits intramembrane proteolysis of pro-sigmaK in an intercompartmental signaling pathway during Bacillus subtilis sporulation. Proc Natl Acad Sci U S A. 101(17):6385-90. Epub 2004 Apr 15. MORE