Screening for the target gene of cyanobacterial cAMP receptor protein SYCRP1

Abstract

Summary The target genes for SYCRP1, a cyanobacterial cAMP receptor protein, were surveyed using a DNA micro‐array method. Total RNAs were extracted from a wild‐type strain and a sycrp1 disruptant of Synechocystis sp. PCC 6803, and the respective gene expression levels were compared. The expression levels of six genes (slr1667, slr1668, slr2015, slr2016, slr2017 and slr2018) were clearly decreased by the disruption of the sycrp1 gene. The data suggest that slr1667 and slr1668 constitute one operon and the other four genes constitute another operon. Transcription start points for the first genes of these putative operons, which are slr1667 and slr2015, were determined by primer extension experiments. Gel mobility shift assays and DNase I footprint analyses were carried out to explore the binding of SYCRP1 to the putative promoter regions of slr1667 and slr2015. SYCRP1 bound to the specific site in the 5′ upstream region of slr1667 from positions –170 to –155 relative to the transcription start point, while it did not bind to the 5′ upstream region of slr2015. It was concluded that SYCRP1 regulates the expression of the slr1667 gene directly by binding to a specific site in its promoter.

SPR analysis of promoter binding of Synechocystis PCC6803 transcription factors NtcA and CRP suggests cross‐talk and sheds light on regulation by effector molecules

“…This question is pertinent, since some cyanobacteria have CRP protein-encoding genes [7], as in Synechocystis sp. PCC6803 (from now on termed Synechocystis), where a CRP protein called Synechocystis CRP (SYCRP1) is expressed from the homonymous gene and transcriptionally regulates expression of a number of genes such as cccS in a cAMP-dependent manner [6,8,9]. Even in cyanobacteria in which there is no gene encoding CRP (such as Synechococcus elongatus), screening methods [7] detect several CRP boxes having an uncertain function, which could be the targets of NtcA regulation.…”

“…While CRP is activated by cAMP [5,8,9], NtcA is activated by 2-oxoglutatare (2OG) [10,11], an indicator of the cellular nitrogen level [12], and it is coactivated by a small (10 kDa) monomeric protein called PII-interacting protein X (PipX) [13,14] (Fig. 1).…”

Integration of Carbon and Nitrogen Metabolism with Energy Production Is Crucial to Light Acclimation in the CyanobacteriumSynechocystis

“…Slr1687 contains a phycobilisome lyase HEATlike domain suggested to being involved in the degradation of phycobilisomes. The slr1667 and slr1668 genes are transcriptionally regulated by Sycrp1 in response to intracellular cAMP (Yoshimura et al, 2002). The sll1894 gene encodes a riboflavin biosynthesis protein RibA.…”

The competence gene, comF, from Synechocystis sp. strain PCC 6803 is involved in natural transformation, phototactic motility and piliation

“…strain PCC 6803 (Yoshihara et al, 2001). A functional Tfp apparatus is also critical for phototaxis, while the regulatory signals and pathways underlying the cells' response to light are rapidly being unravelled (Bhaya, 2004;Bhaya et al, 2001;Fiedler et al, 2005;Yoshihara et al, 2000;Yoshimura et al, 2002). It is apparent that transformability and phototaxis in Synechocystis sp.…”