Sumiko Inouye Associate Professor UMDNJ RWJ Medical School Department of Biochemistry 675 Hoes Lane Piscataway. NJ 08854 (732) 235-4161 FAX - 4559 sinouye@umdnj.edu

Development-specific gene expression. signal transduction during differentiation. eukaryotic-like protein kinases. bacterial retroelements. reverse transcriptase

We have been studying the molecular biology of Myxobacteria. Myxobacteria are gram-negative gliding bacteria that live in soil and feed upon microorganisms and organic debris. behaving cooperatively. Upon starvation. they undergo spectatular multicellular development forming fruiting bodies within which some cells differentiating into spores. Myxobacteria provide an ideal system for the study of various aspects of gene expression. intercellular communication and signal transduction during development as described below.

Signal Transduction During Differentiation - We found the Myxococcus xanthus. a Myxobacterium. contains at least 13 different kinds of protein Ser/Thr kinase similar to that found in the eukaryotes. From their nucleotide sequences. many of these protein kinases have been found to be transmembrane proteins which may sense environmental signals and are involved in various signal transduction pathways to regulate gene expressions leading to the growth and developmental cycle of M. xanthus.

In order to elucidate the signal transduction pathways of these kinases. we applied yeast two hybrid system using M. xanthus chromosomal DNA library and each kinase as a bait. We identified several associated proteins including two new protein Ser/Thr kinases. a phosphatase and other adapter-like proteins. We are currently studying these proteins biochemically and molecular biologically. We also create their deletion mutants to understand their functions in theM. xanthus life cycle.

Another approach to identify substrates of protein Ser/Thr kinases in M. xanthus. we can isolate several suppressor genes from M. xanthus chromosomal DNA library using toxidity of expression of M. xanthus protein kinases in E. coli and we are currently characterizing them.

Molecular Biology of retroelement in prokaryotes - We have found that M. xanthus. as well as E. coli. contain a peculiar satellite DNA called msDNA. MsDNA consists of a single-stranded DNA that is branched out from an internal guanosine residue of a RNA molecule by a 2:5' phosphodiester linkage. We have shown that reverse transcriptase is required for msDNA synthesis. and are not using purified reverse transcriptase to investigate the mechanisms involved in the biosynthesis of msDNA. We are also exploring a possible relationship with eukaryotic retroelements.

Selected Publications

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. 104(19):7969-74.

Ueki T, Inouye S. (2006) A novel regulation on developmental gene expression of fruiting body formation in Myxobacteria. Appl Microbiol Biotechnol. 72(1):21-9.

Nariya H. Inouye S. (2006) A protein Ser/Thr kinase cascade negatively regulates the DNA-binding activity of MrpC. a smaller form of which may be necessary for the Myxococcus xanthus development. Mol Microbiol. 60(5):1205-17.

Nariya H. Inouye S. (2005) Factors that modulate the Pkn4 kinase cascade in Myxococcus xanthus. J Mol Microbiol Biotechnol. 9(3-4):147-53.

Ueki T. Xu CY. Inouye S. (2005) SigF. a new sigma factor required for a motility system of Myxococcus xanthus. J Bacteriol. 187(24):8537-41.

Ueki T. Inouye S. (2005) Activation of a development-specific gene. dofA. by FruA. an essential transcription factor for development of Myxococcus xanthus. J Bacteriol. 187(24):8504-6.

Nariya H. Inouye S. (2005) Identification of a protein Ser/Thr kinase cascade that regulates essential transcriptional activators in Myxococcus xanthus development. Mol Microbiol. 58(2):367-79.

Ueki T. Inouye S. (2005) Identification of a gene involved in polysaccharide export as a transcription target of FruA. an essential factor for Myxococcus xanthus development. J Biol Chem. 280(37):32279-84.

Otani M. Ueki T. Kozuka S. Segawa M. Sano K. Inouye S. (2005)Characterization of a small heat shock protein. Mx Hsp16.6. of Myxococcus xanthus. J Bacteriol. 187(15):5236-41.

Nariya H. Inouye S. (2005) Modulating factors for the Pkn4 kinase cascade in regulating 6-phosphofructokinase in Myxococcus xanthus. Mol Microbiol. 56(5):1314-28.

Inouye M. Ke H. Yashio A. Yamanaka K. Nariya H. Shimamoto T. Inouye S. (2004) Complex formation between a putative 66-residue thumb domain of bacterial reverse transcriptase RT-Ec86 and the primer recognition RNA. J Biol Chem. 279(49):50735-42.

Ueki T. Inouye S. (2003) Identification of an activator protein required for the induction of fruA. a gene essential for fruiting body development in Myxococcus xanthus. Proc Natl Acad Sci U S A. 100(15):8782-7.

Nariya H. Inouye S. (2003) An effective sporulation of Myxococcus xanthus requires glycogen consumption via Pkn4-activated 6-phosphofructokinase. Mol Microbiol. 49(2):517-28.

Akiyama T. Inouye S. Komano T. (2003) Novel developmental genes. fruCD. of Myxococcus xanthus: involvement of a cell division protein in multicellular development. J Bacteriol. 185(11):3317-24.

Horiuchi T. Akiyama T. Inouye S. Komano T. (2003) Regulation of FRUA expression during vegetative growth and development of Myxococcus xanthus. J Mol Microbiol Biotechnol. 5(2):87-96.

Lampson BC. Xu C. Rice SA. Inouye S. (2002) A partial copy of msDNA from a new retron element is likely a retrotransposed DNA found in the myxobacterium Nannocystis exedens. Gene. 299(1-2):251-61.

Nariya H. Inouye S. (2002) Activation of 6-phosphofructokinase via phosphorylation by Pkn4. a protein Ser/Thr kinase of Myxococcus xanthus. Mol Microbiol. 46(5):1353-66.

Horiuchi T. Akiyama T. Inouye S. Komano T. (2002) Analysis of dofA. a fruA-dependent developmental gene. and its homologue. dofB. in Myxococcus xanthus. J Bacteriol. 184(24):6803-10.

Horiuchi T. Taoka M. Isobe T. Komano T. Inouye S. (2002) Role of fruA and csgA genes in gene expression during development of Myxococcus xanthus. Analysis by two-dimensional gel electrophoresis. J Biol Chem. 277(30):26753-60.

Ueki T. Inouye S. (2002) Transcriptional activation of a heat-shock gene. lonD. of Myxococcus xanthus by a two component histidine-aspartate phosphorelay system. J Biol Chem. 277(8):6170-7.

Ueki. T. and Inouye. S. (2001) SigB. SigC. and SigE from Myxococcus xanthus homologous to _32 are not required for heat shock response but for multicellular differentiation. J. Mol. Microbiol. Biotechnol. 3: 287-293.