Dr. William Margolin

Regular Member

The University of Texas Health Science Center at Houston
Medical School
Department of Microbiology and Molecular Genetics

Research Interests:

• Bacterial cell division
• DNA replication
• Rhizobium
• Plant-microbe interactions
• Cellular differentiation

Cell division, or cytokinesis, is a fundamental requirement for the proliferation of all cells. Cytokinesis is regulated temporally and spatially to insure that daughter cells contain the normal complement of chromosomes. We study the regulation of cell division in bacteria, which enables us to use highly sophisticated genetic approaches. Despite our vast knowledge of prokaryotic biology, we still understand surprisingly little about how bacteria, such as Escherichia coli, divide by binary fission.

One of the cell division proteins we focus on is FtsZ, a bacterial homolog of tubulin. FtsZ is an abundant protein that, in response to an unknown signal, polymerizes into a ring structure marking the division site and is essential for the initiation of cell division. Other essential proteins are then recruited to the FtsZ ring and act in a putative complex to complete division. FtsZ is ubiquitous, with homologs in eubacteria, archaea and eukaryotic organelles.

Our long-term goals are to understand how FtsZ and other cell cycle proteins target precisely to the division site and achieve the constrictive force necessary for cytokinesis. We have proposed a new model for placement of the division site that involves both a signal from the bacterial nucleoid as well as a remarkable roving protein complex that migrates from cell pole to cell pole. Also of interest to us is the diversity of cell division mechanisms among microorganisms, and the general mechanism of protein targeting.

A tutorial in my laboratory will provide experience in molecular cloning, DNA sequence analysis, mutagenesis, protein biochemistry, immunodetection assays, and fluorescence microscopy.

Selected Publications: