High impact information on psbB

• Characterization of Mbb1, a nucleus-encoded tetratricopeptide-like repeat protein required for expression of the chloroplast psbB/psbT/psbH gene cluster in Chlamydomonas reinhardtii [1].
• By introducing chimeric genes consisting of sequences from psbB and the reporter gene aadA into the chloroplast, the target site of Mbb1 was mapped in the psbB 5' untranslated region (UTR) [2].
• The chloroplast gene psbB encodes the chlorophyll-a binding protein P5 (CP47), one of the core subunits of photosystem II (PSII) [2].
• Thus, psbB/T and psbH may be independently transcribed, and the latter gene seems to have its own promoter in C. reinhardtii [3].
• Likewise, interruption of psbB/T and psbH with a strong transcriptional terminator from the rbcL gene does not influence transcript accumulation [3].

Biological context of psbB

• We show that the C. reinhardtii psbB gene is co-transcribed with a small open reading frame that is highly conserved in location and amino acid sequence in land plants [4].
• To dissect the expression of the psbB gene cluster of the Chlamydomonas reinhardtii chloroplast genome and to assess the role of the photosystem II H-phosphoprotein (PSII-H) in the biogenesis and/or stabilization of PSII, an aadA gene cassette conferring spectinomycin resistance was employed for mutagenesis [3].
• It is unclear whether a psbB operon is transcribed to yield a large polycistronic precursor but northern blot analysis with total RNA from cells grown at 15 degrees C does not detect an increased complexity of the transcripts, as has been found in studies of the psbB operon of higher plants [5].

Anatomical context of psbB

• Transcripts containing the 5' untranslated regions of the plastid genes psbA and psbB from higher plants are unstable in Chlamydomonas reinhardtii chloroplasts [6].

Other interactions of psbB

• The psbB gene cluster of the Chlamydomonas reinhardtii chloroplast: sequence and transcriptional analyses of psbN and psbH [5].

References