Laurel Bender
lbender@indiana.edu

Indiana University
Department of Biology
Jordan Hall Rm127
1001 East 3rd St.
Bloomington, IN 47405-3700 USA

Advisors:
Dr. Susan Strome, Department of Biology, IU

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Research Interests


Isolated gonad of an adult C. elegans hermaphrodite stained with an antibody to the chromatin-associated MES-4 protein (green) and counterstained to show total chromatin (red). MES-4 is expressed in the distal, mitotic germ cells (left end of the gonad). Its level drops off as germ cells enter mitosis, and rises again during the late pachytene stage of meiosis.
Germ cells differ fundamentally from somatic cells in being immortal. I am interested in the special needs of the germline throughout development. As a member of Susan Strome's lab, I study germline development and maintenance in the nematode C. elegans. The adult worm contains only ~1000 somatic cells and ~1000 germ cells, organized into a relatively simple body plan. The worm's genome is small and has been completely sequenced; thus we have access to all of the worm's genes. We use forward and reverse genetic strategies, including dsRNA interference (RNAi), to knock out selected genes.

The C. elegans proteins MES-2, MES-3, MES-4 and MES-6 are required for the survival and proliferation of the germline, and thus are necessary for its immortality. MES-2 and MES-6 are both members of the Polycomb group of genes, which in Drosophila regulate chromatin structure and gene expression. MES-3 is novel, and MES-4 contains a SET-domain motif and other features characteristic of histone methyltransferases (although we have no evidence yet that MES-4 is an HMT). All four MES proteins localize to germline chromatin. MES-4 binds specifically to autosomes and not to X chromosomes. Based on several lines of evidence, we propose a model in which MES-2, MES-3 and MES-6 form a complex that binds to chromatin to repress transcription, while MES-4 binds just to autosomes to protect them from the repressive effects of the MES-2/3/6 complex (Fong et al., 2002). This model meshes with recent reports that the X chromosomes appear to be transcriptionally repressed in the C. elegans germline (Reinke et al., Molec. Cell 6:605, 2000; Kelly et al., Development 129:479, 2002).

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Publications

  • Fong, Y., Bender, L., Wang, W. and Strome, S. (2002) Regulation of the different states the autosomes and X chromosomes in the germline of C. elegans.  Science 296(5576), 2235-2238.
  • Bender, L., Kooh, P. and Muskavitch, M. (1993) Complex function and expression of Delta during Drosophila oogenesis. Genetics 133:967-978.

 

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OVERVIEW M TRAINING M SEMINARSM PEOPLE M RESEARCH

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