Anabaena sp. strain PCC 7120 conR contains a LytR-CpsA-Psr domain, is developmentally regulated, and is essential for diazotrophic growth and heterocyst morphogenesis.
Microbiology (Reading)
; 157(Pt 3): 617-626, 2011 Mar.
Article
en En
| MEDLINE
| ID: mdl-21088107
ABSTRACT
The conR (all0187) gene of the filamentous cyanobacterium Anabaena (Nostoc) sp. strain PCC 7120 is predicted to be part of a family of proteins that contain the LytR-CpsA-Psr domain associated with septum formation and cell wall maintenance. The conR gene was originally misannotated as a transcription regulator. Northern RNA blot analysis showed that conR expression was upregulated 8 h after nitrogen step-down. Fluorescence microscopy of a P(conR)-gfp reporter strain revealed increased GFP fluorescence in proheterocysts and heterocysts beginning 9 h after nitrogen step-down. Insertional inactivation of conR caused a septum-formation defect of vegetative cells grown in nitrate-containing medium. In nitrate-free medium, mutant filaments formed abnormally long heterocysts and were defective for diazotrophic growth. Septum formation between heterocysts and adjacent vegetative cells was abnormal, often with one or both poles of the heterocysts appearing partially open. In a conR mutant, expression of nifH was delayed after nitrogen step-down and nitrogenase activity was approximately 70â% of wild-type activity, indicating that heterocysts of the conR mutant strain are partially functional. We hypothesize that the diazotrophic growth defect is caused by an inability of the heterocysts to transport fixed nitrogen to the neighbouring vegetative cells.
Texto completo:
1
Banco de datos:
MEDLINE
Asunto principal:
Proteínas Bacterianas
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Regulación Bacteriana de la Expresión Génica
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Anabaena
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Fijación del Nitrógeno
Idioma:
En
Revista:
Microbiology (Reading)
Asunto de la revista:
MICROBIOLOGIA
Año:
2011
Tipo del documento:
Article
País de afiliación:
Estados Unidos