HesF, an exoprotein required for filament adhesion and aggregation in Anabaena sp PCC 7120

• Tipo: Artigo em Revista Científica Internacional
• Data: 2015

Autores

Paulo Oliveira (Autor) Outra; Filipe Pinto (Autor) Outra; Catarina C Pacheco (Autor) Outra; Rita Mota (Autor) Outra; Paula Tamagnini (Autor) FCUP

Revista

Título: Environmental Microbiology

Vol. 17

Páginas: 1631-1648

ISSN: 1462-2912

Editora: Wiley-Blackwell

Indexação

ISI Web of Knowledge - 23 Citações

Scopus - 24 Citações

Classificação Científica

FOS: Ciências exactas e naturais > Ciências biológicas

CORDIS: Ciências Naturais > Ciências biológicas > Biologia > Microbiologia

Outras Informações

ID Authenticus: P-00A-CHC

DOI: 10.1111/1462-2920.12600

Abstract (EN): Here, we report on the identification and characterization of a protein (Alr0267) named HesF, found in the extracellular milieu of Anabaena sp. PCC 7120 grown diazotrophically. hesF was found to be highly upregulated upon transition from non-nitrogen-fixing to nitrogen-fixing conditions, and the highest transcript levels were detected towards the end of the heterocyst differentiation process. The hesF promoter drives transcription of the gene in heterocysts only, and both NtcA and HetR are essential for the gene's in vivo activation. An examination of HesF's translocation showed that the secretion system is neither heterocyst-specific nor dependent on nitrogen-fixing conditions. Furthermore, HesF was found to be a type I secretion system substrate, since an HgdD mutant failed to secrete HesF. Several analyses revealed that a HesF minus mutant strain lacks the heterocyst-specific polysaccharide fibrous layer, accumulates high amounts of polysaccharides in the medium and that HesF is essential for the typical aggregation phenotype in diazotrophic conditions. Thus, we propose that HesF is a carbohydrate-binding exoprotein that plays a role in maintaining the heterocyst cell wall structure. A combination of and possibly interaction between HesF and heterocyst-specific polysaccharides seems to be responsible for filament adhesion and culture aggregation in heterocyst-forming cyanobacteria.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 18