From: ncbi-seminar-admin@ncbi.nlm.nih.gov on behalf of Kira Makarova
[makarova@ncbi.nlm.nih.gov]
Sent: Thursday, October 03, 2002 3:52 PM
To: ncbi-seminar@ncbi.nlm.nih.gov
Subject: CBB seminar

NCBI SEMINAR ANNOUNCEMENT

Monday October 7, 11 AM,
Natcher (Bldg 45) 6th Floor South Conference Room (6AS29)

Radiation-resistant bacterium Deinococcus radiodurans: comparative and functional genomics

Kira Makarova, NCBI


	Deinococcus radiodurans is a bacterium best known for its extreme resistance to the lethal effects of
ionizing radiation. Extensive comparative-genomic analysis revealed a number of interesting features in
Deinococcus genome but failed to unequivocally establish molecular mechanisms responsible for these
unique radiation-resistant capabilities. It has been concluded that this phenotype is complex, likely
determined collectively by some of the features revealed by genome analysis, as well as may be
attributable to still unknown genes and pathways or more subtle structural peculiarities of proteins and
DNA. Recently Deinococcus transcriptome dynamics was examined in cells representing early, middle, and
late phases of recovery after acute irradiation doze (15 kGy) using DNA microarrays analysis covering
~94% of its predicted genes. Several independent approaches for analysis of the data quality were
applied. The expression patterns of the majority of the induced genes resemble the previously
characterized expression profile of recA following irradiation. Many other genes were expressed later in
recovery, displaying a growth-related pattern of induction. Genes induced in the early phase of recovery
included those involved in DNA replication, repair, recombination, cell wall metabolism, cellular
transport, and many encoding uncharacterized proteins. Thus, the microarray data suggest that
Deinococcus cells efficiently coordinate their recovery by a complex network, within which both DNA
repair and metabolic functions play critical roles. Components of this network include a predicted
distinct ATP-dependent DNA ligase and metabolic pathway switching that could prevent additional genomic
damage. Microarray data will aid further experimental studies on transcriptional regulation of this
specific response and on a role of several yet uncharacterized proteins that are significantly induced
after irradiation. 
	DNA microarrays analysis is a joint work with Oak Ridge National Laboratory, TN and
Michael Daly's laboratory from Department of Pathology, Uniformed Services University of the Health Sciences, 
MD.