Alterations in oxygen tension are known to affect gene expression in all cell types. In bacterial systems, oxygen affects expression of a variety of genes involved in aerobic versus anaerobic energy generation such as nitrate reductase and cytochrome oxidase. The presence of oxygen reactive species, also affects expression of genes involved in defense against oxidative damage. A variety of additional metabolic processes such as carbon fixation, nitrogen fixation, and anoxygenic photosynthesis are also regulated in response to the presence or absence of oxygen. In yeast and algal cells, oxygen is known to affect transcription of oxidative defense genes as well as enzymes involved glycolysis. In mammalian cells, a growing number of genes are known to be oxygen regulated such as those coding for growth factors such as erythropoietin and vascular endothelithial growth factors that are key regulators for the synthesis of new capillary sprouts from preexisting vessels. Besides physiological roles, these growth factors are also involved in disease processes such as the stimulation of capillary formation during tumor growth. This proposal is centered on elucidating molecular details of how oxygen affects gene expression in bacteria. As a model system, we study oxygen regulated gene expression in Rhodobacter capsulatus which is closely related to the mitochondrial lineage. This species is capable of growth in a variety of energy generating modes including aerobic respiration, anaerobic fermentation and photosynthesis. The expression of genes involved in each of these processes is known to be affected by alterations in oxygen tension and well as by variations in light intensity. As such, this organism offers itself as an important model system to the study oxygen and light regulation of gene expression in a number of biological systems.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM040941-17
Application #
6830739
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Program Officer
Anderson, James J
Project Start
1989-12-01
Project End
2006-03-31
Budget Start
2004-12-01
Budget End
2006-03-31
Support Year
17
Fiscal Year
2005
Total Cost
$300,661
Indirect Cost
Name
Indiana University Bloomington
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
006046700
City
Bloomington
State
IN
Country
United States
Zip Code
47401
Fang, Mingxu; Bauer, Carl E (2018) Regulation of stringent factor by branched-chain amino acids. Proc Natl Acad Sci U S A 115:6446-6451
Yamamoto, Haruki; Fang, Mingxu; Dragnea, Vladimira et al. (2018) Differing isoforms of the cobalamin binding photoreceptor AerR oppositely regulate photosystem expression. Elife 7:
Kumka, Joseph E; Schindel, Heidi; Fang, Mingxu et al. (2017) Transcriptomic analysis of aerobic respiratory and anaerobic photosynthetic states in Rhodobacter capsulatus and their modulation by global redox regulators RegA, FnrL and CrtJ. Microb Genom 3:e000125
Fang, Mingxu; Bauer, Carl E (2017) The Vitamin B12-Dependent Photoreceptor AerR Relieves Photosystem Gene Repression by Extending the Interaction of CrtJ with Photosystem Promoters. MBio 8:
Shimizu, Takayuki; Shen, Jiangchuan; Fang, Mingxu et al. (2017) Sulfide-responsive transcriptional repressor SqrR functions as a master regulator of sulfide-dependent photosynthesis. Proc Natl Acad Sci U S A 114:2355-2360
Cheng, Zhuo; Yamamoto, Haruki; Bauer, Carl E (2016) Cobalamin's (Vitamin B12) Surprising Function as a Photoreceptor. Trends Biochem Sci 41:647-650
Schindel, Heidi S; Bauer, Carl E (2016) The RegA regulon exhibits variability in response to altered growth conditions and differs markedly between Rhodobacter species. Microb Genom 2:e000081
Shimizu, Takayuki; Cheng, Zhuo; Matsuura, Katsumi et al. (2015) Evidence that Altered Cis Element Spacing Affects PpsR Mediated Redox Control of Photosynthesis Gene Expression in Rubrivivax gelatinosus. PLoS One 10:e0128446
Kumka, Joseph E; Bauer, Carl E (2015) Analysis of the FnrL regulon in Rhodobacter capsulatus reveals limited regulon overlap with orthologues from Rhodobacter sphaeroides and Escherichia coli. BMC Genomics 16:895
Vermeulen, Arjan J; Bauer, Carl E (2015) Members of the PpaA/AerR Antirepressor Family Bind Cobalamin. J Bacteriol 197:2694-703

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