ISSN:
1617-4623
Keywords:
D1 polypeptide
;
Gene regulation
;
psbA
;
RNA stability
;
Synechocystis
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract The 5′ region and transcription initiation sites of the psbA-2 and psbA-3 genes of Synechocystis 6803 were determined. The otherwise highly homologous genes were shown to diverge significantly in the 5′ noncoding regions. The transcription start site for the psbA-2 gene was mapped to position — 49 upstream of the coding region and for the psbA-3 gene to position — 88, i.e. 38 by upstream of the psbA-2 transcription start point. Both genes exhibit promoter elements, which conform in sequence and position to Escherichia coli consensus motifs. The two genes share identical — 35 sequences but differ in their — 10 sequences. Primer extension analysis demonstrated that the psbA-2 and psbA-3 genes are differentially expressed, with 〉 90 % of the total psbA transcripts being produced by the psbA-2 gene and the rest by the psbA-3 gene. Inactivation of the psbA-2 gene resulted in an eightfold up-regulation of the psbA-3 gene. The strikingly higher stability of the psbA transcripts in darkness compared to light, and the accumulation of a specific decay intermediate under dark conditions was reported previously. We show here that this dark-stability applies to both the psbA-2 and psbA-3 transcripts. The psbA-3 transcript did not appear to produce the processed intermediate, arguing for the involvement of the 5′ non-coding region as a determinant in psbA transcript degradation.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00279543
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