Tuesday, May 9, 11 AM

Bldg. 38A, 8th floor conference room

Mycoplasmas and the minimal genome problem

Clyde A. Hutchison, 3rd

Department of Microbiology and Immunology, University of North Carolina, Chapel
Hill

Mycoplasma genitalium with 517 genes has the smallest gene complement of
any independently replicating cell so far identified.  To understand
whether the naturally occurring gene complement is a true minimal genome
under laboratory growth conditions, global transposon mutagenesis was used
to identify nonessential genes.  The position of 2,209 transposon
insertions in the completely sequenced genomes of M. genitalium, and its
close relative M. pneumoniae, were determined by sequencing across the
junction of the transposon and the genomic DNA. These junctions defined
1,354 distinct sites of insertion that were not lethal. This information
has allowed us to make a preliminary catalog of the nonessential genes in
these mycoplasmas. The analysis suggests that 265-350 of the 480 protein
coding genes of M. genitalium are essential under laboratory growth
conditions, including approximately 100 genes of unknown function. A few
of the transposon insertions were in genes generally believed to be
essential. Possible implications of these surprising events will be
discussed.

-- 
Eugene V. Koonin, PhD
National Center for Biotechnology Information
National Library of Medicine
National Institutes of Health, Bldg. 38A, Rm. 5N505A (5th floor)
Bethesda, MD 20894, USA
Voice: (301)435-5913
Fax: (301)480-9241
email koonin@ncbi.nlm.nih.gov