Expression of the psbDII gene in Synechococcus sp. strain PCC 7942 requires sequences downstream of the transcription start site

Bustos, Silvia A.; Golden, Susan S.

doi:10.1128/jb.173.23.7525-7533.1991

Cited by 122 publications

(76 citation statements)

References 44 publications

(48 reference statements)

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“…Culture Conditions-The mesophilic cyanobacterium S. elongatus PCC 7942 WT (39) and mutant strains were grown in BG-11M medium (40) as 100-ml cultures in CO 2 -enriched air (1%) at a light intensity (photosynthetic photon flux density) of 150 microeinsteins m Ϫ2 s…”

Section: Methodsmentioning

confidence: 99%

Biochemical Properties of CikA, an Unusual Phytochrome-like Histidine Protein Kinase That Resets the Circadian Clock in Synechococcus elongatus PCC 7942

Mutsuda

Michel

Zhang

et al. 2003

Journal of Biological Chemistry

111

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We recently described the cikA (circadian input kinase A) gene, whose product supplies environmental information to the circadian oscillator in the cyanobacterium Synechococcus elongatus PCC 7942. CikA possesses three distinct domains: a GAF, a histidine protein kinase (HPK), and a receiver domain similar to those of the response regulator family. To determine how CikA functions in providing circadian input, we constructed modified alleles to tag and truncate the protein, allowing analysis of each domain individually. CikA covalently bound bilin chromophores in vitro, even though it lacks the expected ligand residues, and the GAF domain influenced but did not entirely account for this function. Full-length CikA and truncated variants that carry the HPK domain showed autophosphorylation activity. Deletion of the GAF domain or the N-terminal region adjacent to GAF dramatically reduced autophosphorylation, whereas elimination of the receiver domain increased activity 10-fold. Assays to test phosphorelay from the HPK to the cryptic receiver domain, which lacks the conserved aspartyl residue that serves as a phosphoryl acceptor in response regulators, were negative. We propose that the cryptic receiver is a regulatory domain that interacts with an unknown protein partner to modulate the autokinase activity of CikA but does not work as bona fide receiver domain in a phosphorelay.

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Section: Methodsmentioning

confidence: 99%

Biochemical Properties of CikA, an Unusual Phytochrome-like Histidine Protein Kinase That Resets the Circadian Clock in Synechococcus elongatus PCC 7942

Mutsuda

Michel

Zhang

et al. 2003

Journal of Biological Chemistry

111

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“…strain PCC 7942 were grown in modified BG-11 medium (Bustos and Golden, 1991). Cells were first grown as 100 ml cultures in shaking flasks without any antibiotics (we have previously determined that neutral-site insertions are stable without continuous selection).…”

Section: Culture Conditionsmentioning

confidence: 99%

mRNA stability is regulated by a coding‐region element and the unique 5′ untranslated leader sequences of the three Synechococcus psbA transcripts

Kulkarni

Golden

1997

Molecular Microbiology

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SummaryThe psbAI and psbAIII transcripts in Synechococcus sp. strain PCC 7942 are subject to accelerated turnover when cells are exposed to high light intensities, but psbAII message stability is unaffected. We used a psbAI 'minigene' which has a part of the coding sequence removed as a reporter gene in order to identify the cis-acting elements of the transcript that determine stability. While engineering the minigene to optimally mimic the native gene, we identified a stabilizer element within the open reading frame, corresponding to the coding region for the first membrane span of the D1 protein, the presence of and translation through which was essential for normal psbA mRNA stability. We propose that this stabilizer is a site for ribosome pausing, and that accumulation of ribosomes on the transcript upstream of the pause site increases stability. To identify the elements that regulate the differential responses of the psbA transcripts to high-light growth, sequences from psbAII and psbAIII were substituted in the psbAI minigene reporter. The chimeric reporter transcripts established that the psbAI and psbAIII untranslated leaders determine the faster turnover of these messages. The untranslated leader regions of the psbA transcripts may regulate mRNA stability by modulating translation and thereby stability, or by recruiting RNA-binding proteins that affect mRNA turnover more directly.

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“…Plasmid pAM854 (Bustos and Golden, 1991) is a Synechococcus recombinational transformation vector comprising pBR328 containing a 2.8-kb BamHI fragment of Synechococcus genomic DNA inserted at a unique BamHI site in the vector. A modified spectinomycin/streptomycin resistance cassette was inserted into a XhoI site within the Synechococcus DNA.…”

Section: Cloning Of Rapeseed and Soybean Cdnas Encodingmentioning

confidence: 99%

Cloning of a Higher-Plant Plastid [omega]-6 Fatty Acid Desaturase cDNA and Its Expression in a Cyanobacterium

Hitz¹,

Carlson²,

Booth³

et al. 1994

Plant Physiol.

113

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Oligomers based on amino acids conserved between known plant w-3 and cyanobacterium w -6 fatty acid desaturases were used to screen an Arabidopsis cDNA library for related sequences. An identified clone encoding a novel desaturase-like polypeptide was used to isolate its homologs from Glycine mar and Brassica napus. The plant deduced amino acid sequences showed less than 27% similarity to known plant w -6 and w-3 desaturases but more than 48% similarity to cyanobacterial w-6 desaturase, and they contained putative plastid transit sequences. Thus, we deduce that the plant cDNAs encode the plastid w-6 desaturase. l h e identity was supported by expression of the B. napus cDNA in cyanobaderium.Synechococcus transformed with a chimeric gene that contains a prokaryotic promoter fused to the rapeseed cDNA encoding all but the first 7 3 amino acids partially converted its oleic acid fatty acid to linoleic acid, and the 161(9c) fatty acid was converted primarily to 162(9c,12) in vivo. lhus, the plant w -6 desaturase, which utilizes 16:1(7c) in plants, can utilize 161(9c) in the cyanobaderium. l h e plastid and cytosolic homologs of plant w-6 desaturases are much more distantly related than those of w-3 desaturases.In leaf tissue there are two distinct pathways for the biosynthesis of the polyunsaturated fatty acids 1 8 2 and 18:3, one located in cytosolic membranes and the other located in plastid membranes. In Arabidopsis thaliana, cytosolic and plastid w-6 fatty acid desaturations that result in the production of diene fatty acids are controlled by the FAD 2 and FAD 6 loci, respectively. Cytosolic and plastid w-3 desaturations that result in the production of triene fatty acids are controlled by FAD 3 and FAD 7, respectively (Lemieux et al., 1990;Browse and Somerville 1991). It has been postulated that these loci correspond to structural genes for the desaturase enzymes. For FAD 3, proof of this postulate has come from the cloning of a cDNA encoding a desaturase corresponding to the FAD 3 locus (Arondel et al., 1992; Yadav et al., 1993).Cytosolic w-3 fatty acid desaturase cDNAs have been used to isolate their plastid homologs by screening plant cDNA libraries under low-stringency hybridization conditions, and the amino acid sequences of the higher-plant 0-3 desaturases show significant similarity (68% or greater) both among different plant species and between the microsomal and plastid homologs within each species (Iba et al., 1993; Yadav et al., 1993). However, this screening did not result in the isolation of cDNAs encoding other than w-3 desaturases.* Corresponding author; fax 1-302-695-4296.Recently, the T-DNA tagging method was used to isolate the Arabidopsis microsomal w-6 fatty acid desaturase (FAD 2) and it showed only 36% similarity at the amino acid leve1 with the w-3 desaturases (Okuley et al., 1994). In contrast to the results with w-3 desaturases, low-stringency screening of an Arabidopsis cDNA library with the Arabidopsis microsomal w-6 desaturase cDNA did not result in the identification of its plastid...

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Expression of the psbDII gene in Synechococcus sp. strain PCC 7942 requires sequences downstream of the transcription start site

Cited by 122 publications

References 44 publications

Biochemical Properties of CikA, an Unusual Phytochrome-like Histidine Protein Kinase That Resets the Circadian Clock in Synechococcus elongatus PCC 7942

Biochemical Properties of CikA, an Unusual Phytochrome-like Histidine Protein Kinase That Resets the Circadian Clock in Synechococcus elongatus PCC 7942

mRNA stability is regulated by a coding‐region element and the unique 5′ untranslated leader sequences of the three Synechococcus psbA transcripts

Cloning of a Higher-Plant Plastid [omega]-6 Fatty Acid Desaturase cDNA and Its Expression in a Cyanobacterium

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