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N and C control of ABC‐type bicarbonate transporter Cmp and its LysR‐type transcriptional regulator CmpR in a heterocyst‐forming cyanobacterium, Anabaena sp.
Author(s) -
LópezIgual Rocío,
Picossi Silvia,
LópezGarrido Javier,
Flores Enrique,
Herrero Antonia
Publication year - 2012
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/j.1462-2920.2011.02683.x
Subject(s) - biology , transcriptional regulation , regulator , anabaena , heterocyst , gene , transcription factor , transcription (linguistics) , microbiology and biotechnology , genetics , cyanobacteria , bacteria , linguistics , philosophy
Summary In the model, heterocyst‐forming cyanobacterium Anabaena sp. PCC 7120, gene cluster alr2877‐alr2880 , which encodes an ABC‐type transport system, was induced under conditions of carbon limitation and its inactivation impaired the uptake of bicarbonate. Thus, this gene cluster encodes a Cmp bicarbonate transporter. ORF all0862 , encoding a LysR‐type transcriptional regulator, was expressed under carbon limitation and at higher levels in the absence than in the presence of combined nitrogen, with a positive effect of the N‐control transcription factor NtcA. all0862 was expressed from two putative transcription start sites located 164 and 64 bp upstream from the gene respectively. The latter was induced under carbon limitation and was dependent on positive autoregulation by All0862. All0862 was required for the induction of the Cmp bicarbonate transporter, thus representing a CmpR regulator of Anabaena sp. These results show a novel mode of co‐regulation by C and N availability through the concerted action of N‐ and C‐responsive transcription factors.