Abstract

The goal of this project is an understanding, in molecular terms, of the processes governing the differentiation of heterocysts, cells specialized for nitrogen fixation, along filaments of the cyanobacterium Anabaena. Although Anabaena is a prokaryote, heterocyst differentiation is characterized by irreversible commitment. The process includes changes in mRNA abundance, vast changes in the synthesis of specific protein, and several cases of rearrangement of DNA. Transcriptional regulation of the differentiation will be studied in vivo and in vitro, using cloned genes as probes of transcription. Many promoter regions have been identified; some of these will be modified by in vitro mutagenesis, returned to Anabaena by conjugation from E. coli, and analyzed on the basis of the activity of reporter genes fused to the modified promoter. Regulation of the process by which DNA around the genes encoding nitrogen fixation functions (nif) is rearranged will be studied by purification of the enzyme(s) responsible for site-specific recombination during heterocyst differentiation in the determination of factors that govern that enzyme's synthesis and activity.

  Funding Agency

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM021823-17
Application #
3270718
Study Section
Microbial Physiology and Genetics Subcommittee 2 (MBC)
Project Start
1978-05-01
Project End
1993-04-30
Budget Start
1991-05-01
Budget End
1992-04-30
Support Year
17
Fiscal Year
1991
Total Cost
Indirect Cost

  Institution

Name
University of Chicago
Department
Type
Schools of Medicine
DUNS #
225410919
City
Chicago
State
IL
Country
United States
Zip Code
60637

  Publications

Jones, Kathryn M; Buikema, William J; Haselkorn, Robert (2003) Heterocyst-specific expression of patB, a gene required for nitrogen fixation in Anabaena sp. strain PCC 7120. J Bacteriol 185:2306-14
Jones, Kathryn M; Haselkorn, Robert (2002) Newly identified cytochrome c oxidase operon in the nitrogen-fixing cyanobacterium Anabaena sp. strain PCC 7120 specifically induced in heterocysts. J Bacteriol 184:2491-9
Callahan, S M; Buikema, W J (2001) The role of HetN in maintenance of the heterocyst pattern in Anabaena sp. PCC 7120. Mol Microbiol 40:941-50
Buikema, W J; Haselkorn, R (2001) Expression of the Anabaena hetR gene from a copper-regulated promoter leads to heterocyst differentiation under repressing conditions. Proc Natl Acad Sci U S A 98:2729-34
Rouhiainen, L; Paulin, L; Suomalainen, S et al. (2000) Genes encoding synthetases of cyclic depsipeptides, anabaenopeptilides, in Anabaena strain 90. Mol Microbiol 37:156-67
Brandon, L; Dorus, S; Epstein, W et al. (2000) Modulation of KdpD phosphatase implicated in the physiological expression of the kdp ATPase of Escherichia coli. Mol Microbiol 38:1086-92
Bauer, C C; Ramaswamy, K S; Endley, S et al. (1997) Suppression of heterocyst differentiation in Anabaena PCC 7120 by a cosmid carrying wild-type genes encoding enzymes for fatty acid synthesis. FEMS Microbiol Lett 151:23-30
Rouhiainen, L; Sivonen, K; Buikema, W J et al. (1995) Characterization of toxin-producing cyanobacteria by using an oligonucleotide probe containing a tandemly repeated heptamer. J Bacteriol 177:6021-6
Bauer, C C; Haselkorn, R (1995) Vectors for determining the differential expression of genes in heterocysts and vegetative cells of Anabaena sp. strain PCC 7120. J Bacteriol 177:3332-6
Black, K; Buikema, W J; Haselkorn, R (1995) The hglK gene is required for localization of heterocyst-specific glycolipids in the cyanobacterium Anabaena sp. strain PCC 7120. J Bacteriol 177:6440-8

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