This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Bauer, C. C. Articles by Haselkorn, R. Search for Related Content PubMed PubMed Citation Articles by Bauer, C. C. Articles by Haselkorn, R.

 Previous Article  |  Next Article 

J. Bacteriol., Mar 1995, 1520-1526, Vol 177, No. 6
Copyright © 1995, American Society for Microbiology

A short-filament mutant of Anabaena sp. strain PCC 7120 that fragments in nitrogen-deficient medium

CC Bauer, WJ Buikema, K Black and R Haselkorn
Department of Molecular Genetics and Cell Biology, University of Chicago 60637.

Strain 129 is a fragmentation mutant of the filamentous cyanobacterium Anabaena sp. strain PCC 7120. Growing with fixed nitrogen, this mutant forms filaments that are much shorter than wild-type filaments. Following starvation for fixed nitrogen, strain 129 becomes nearly unicellular and forms few heterocysts, although electron microscopy suggests that proheterocysts form while fragmentation occurs. Starvation for sulfate, phosphate, iron, and calcium does not cause this fragmentation. The affected gene in strain 129, fraC, was cloned by complementation and characterized. It encodes a unique 179-amino- acid protein rich in phenylalanine. Insertional inactivation of the chromosomal copy of fraC results in a phenotype identical to that of strain 129, while complementation using a truncated version of FraC results in only partial complementation of the original mutant. Heterocysts could be induced to form in N-replete cultures of strain 129, as in wild-type cells, by supplying extra copies of the hetR gene on a plasmid. Thus, FraC is required for the integrity of cell junctions in general but is apparently not directly involved in normal differentiation and nitrogen fixation.

This article has been cited by other articles:

• Flores, E., Pernil, R., Muro-Pastor, A. M., Mariscal, V., Maldener, I., Lechno-Yossef, S., Fan, Q., Wolk, C. P., Herrero, A. (2007). Septum-Localized Protein Required for Filament Integrity and Diazotrophy in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120. J. Bacteriol. 189: 3884-3890 [Abstract] [Full Text]  
• Nayar, A. S., Yamaura, H., Rajagopalan, R., Risser, D. D., Callahan, S. M. (2007). FraG is necessary for filament integrity and heterocyst maturation in the cyanobacterium Anabaena sp. strain PCC 7120. Microbiology 153: 601-607 [Abstract] [Full Text]  
• Khudyakov, I. Y., Golden, J. W. (2001). Identification and Inactivation of Three Group 2 Sigma Factor Genes in Anabaena sp. Strain PCC 7120. J. Bacteriol. 183: 6667-6675 [Abstract] [Full Text]