The analysis of L. majuscula hoxE and xisH promoter regions, selleck products revealed putative binding sites for LexA, using the motif described by Domain et al. [31], and for the integration host fact IHF. It was previously demonstrated that LexA is a transcriptional regulator of the hox genes in Synechocystis sp. PCC 6083 and Nostoc sp. PCC 7120 [28–30], acting as an activator in Synechocystis sp. PCC 6803 [28]. Additionally, LexA was also

suggested to be involved in the transcriptional regulation of hyp genes, encoding the proteins putatively involved in the biosynthesis/maturation of hydrogenases in L. majuscula [1]. Recently, besides LexA, an AbrB-like protein was shown to specifically interact with the Synechocystis sp. PCC 6803 hox promoter region activating the transcription [32]. However, putative recognition

motifs for the AbrB-like protein are not yet described. IHF has been find more described to act together with other transcription factors providing an appropriate deformation of the DNA scaffold activating transcription [33, 34]. Consequently, it is possible that the binding of IHF to the hoxE and xisH promoter regions will promote the Selleck 3Methyladenine bending of the DNA, favouring the contact between the transcription factors associated upstream (LexA) and the RNA polymerase complex. Promoter region and transcription of hupW It has been previously described that, similar to other cyanobacteria, the hupSL genes are cotranscribed in L. majuscula [2, 15]. However, the cotranscription of hupSLW has been demonstrated only for Gloeothece sp. ATCC 27152 [17], while in Nostoc sp. PCC 7120 and N. punctiforme hupW seems to be transcribed independently from hupSL [19]. In L. majuscula, the RT-PCR data shows that hupL might be cotranscribed with hupW but the identification of a transcription start point upstream of hupW suggests that this gene is also transcribed from its own promoter. This is not the first time that the existence Amino acid of different transcripts for the structural hydrogenase genes and its putative

specific C-terminal endopeptidase is reported, since it has previously been shown that hoxW can be part of a transcriptional unit containing hoxUYH, but it is mainly transcribed from its own promoter in Synechococcus sp. PCC 7942 [18]. In L. majuscula, a putative IHF binding site was found in the hupW promoter region, similar to what was reported for the hupSL promoter [2]. It was previously shown that the transcriptional factor NtcA, a protein that operates global nitrogen control in cyanobacteria [35], binds the hupSL genes promoter region of several cyanobacteria, including L. majuscula [2, 15, 36], but no NtcA consensus sequence signature could be recognized in the L. majuscula hupW promoter. It is important to retain that in L.