Disease relevance of chlB

• The C. reinhardtii chlB gene is similar to open reading frame 563 (orf563) of C. moewusii, and its encoded protein is a homolog of the Rhodobacter capsulatus bchB gene product that encodes one of the polypeptide components of bacterial light-independent protochlorophyllide reduction [1].

High impact information on chlB

• A chloroplast-encoded gene, designated chlB, has been isolated from Chlamydomonas reinhardtii, its nucleotide sequence determined, and its role in the light-independent reduction of protochlorophyllide to chlorophyllide demonstrated by gene disruption experiments [1].
• The mutated chlB genes were introduced into the Chlamydomonas chloroplast genome using particle gun-mediated transformation, and homoplasmic transformants containing the disrupted chlB genes were selected on the basis of conversion to antibiotic resistance [1].
• To determine whether the chlB gene product has a similar role in light-independent protochlorophyllide reduction in this alga, a series of plasmids were constructed in which the aadA gene conferring spectinomycin resistance was inserted at three different sites within the chlB gene [1].
• Individual transformed strains containing chlB disruptions were grown in the dark or light, and 17 of the 18 strains examined were found to have a "yellow-in-the-dark" phenotype and to accumulate the chlorophyll biosynthetic precursor protochlorophyllide [1].
• RNA gel blot analysis of chlB gene expression in wild-type cells indicated that the gene was transcribed at low levels in both dark- and light-grown cells [1].

Biological context of chlB

• We have cloned and sequenced a Chlamydomonas moewusii chloroplastic DNA fragment that includes a 563 amino-acid open reading frame (ORF563, chlB) presenting 89% amino-acid homology with ORF513 from Marchantia polymorpha [2].
• Chloroplastic genomes of Ginkgo biloba and Chlamydomonas moewusii contain a chlB gene encoding one subunit of a light-independent protochlorophyllide reductase [2].
• In the chlB transcript of Pinus sylvestris, the editing of the second position in a CCG codon leads to an amino-acid substitution from proline to leucine [3].

Anatomical context of chlB

• Transcripts derived from the three plastid genes, chlL, chlN, and chlB, encoding subunits of the light-independent protochlorophyllide reductase were detected in the cotyledons and stems of dark-grown seedlings, and in mature needles [4].

Other interactions of chlB

• The highest levels of chlL, chlN, and chlB transcripts were detected within the top one-third of the stem and decreased gradually towards the stem/root transition zone [4].

References