Analysis of a Het- mutation in Anabaena sp. strain PCC 7120 implicates a secondary metabolite in the regulation of heterocyst spacing.
AUTOR(ES)
Black, T A
RESUMO
Transposon-generated mutant N10 of Anabaena sp. strain PCC 7120 has a Het- phenotype (A. Ernst, T. Black, Y. Cai, J.-M. Panoff, D. N. Tiwari, and C. P. Wolk, J. Bacteriol. 174:6025-6032, 1992). Reconstruction of the transposon mutation reproduced a Het- phenotype, but reconstructions with other insertions at the position of the transposon produced strains that form multiple contiguous heterocysts. Sequence analysis around the site of insertion of the transposon showed that the insertion lies within the 5' end of an 861-bp open reading frame (ORF) (hetN). The product of translation of hetN (HetN) shows extensive similarity to NAD(P)H-dependent oxidoreductases that are involved in biosyntheses of fatty acids, poly-beta-hydroxybutyrate, nod factor, and polyketides. A second, 1,518-bp ORF (hetM) that ends 556 bp 5' from the start of hetN appears to encode a protein that has at least two functional domains: its amino terminus is similar to an acyl carrier protein, while its central portion is similar to domains of proteins that perform reductive reactions. A third, 711-bp ORF (hetI) encoded on the opposite strand ends 42 bp away from the 3' end of hetN. The protein encoded by hetI, HetI, is similar to Sfp from Bacillus subtilis and EntD from Escherichia coli, proteins that are required for the biosynthesis or export of cyclic peptides. Clones from a lambda-EMBL3 library that contain the wild-type DNA for hetN do not complement the hetN::Tn5-1063 mutation in N10. The presence of hetN, as the only ORF, on a replicating plasmid suppresses heterocyst formation in wild-type cells, whereas the additional presence of hetI alleviates this effect.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=205350Documentos Relacionados
- Anabaena sp. Strain PCC 7120 hetY Gene Influences Heterocyst Development
- hetL Overexpression Stimulates Heterocyst Formation in Anabaena sp. Strain PCC 7120
- Different functions of HetR, a master regulator of heterocyst differentiation in Anabaena sp. PCC 7120, can be separated by mutation
- patS Minigenes Inhibit Heterocyst Development of Anabaena sp. Strain PCC 7120
- Identification of the Active Site of HetR Protease and Its Requirement for Heterocyst Differentiation in the Cyanobacterium Anabaena sp. Strain PCC 7120