A photosystem II polypeptide is encoded by an open reading frame co-transcribed with genes for cytochrome b-559 in wheat chloroplast DNA

Abstract

The N-terminal amino acid sequence of a 3.2 kDa photosystem II polypeptide is shown to be identical to that of a polypeptide encoded by an open reading frame of 38 codons (orf38) in wheat chloroplast DNA. Orf38 is located just downstream of the psbE and psbF genes for the polypeptides of cytochrome b-559. Analysis of the transcription of this region of chloroplast DNA shows that psbE, psbF and orf38 are co-transcribed to give a 1.1 kb polycistronic transcript which also contains another open reading frame of 40 codons. The orf38 and orf40 products are hydrophobic polypeptides which are both predicted to span the thylakoid membrane once. Orf38 and orf40 are highly conserved, and map to similar locations adjacent to psbE and psbF, in all organisms from which this region of DNA has been sequenced. We propose that orf38 is named psbL.

Dynamical behavior of psb gene transcripts in greening wheat seedlings. I. Time course of accumulation of the psbA through psbN gene transcripts during light-induced greening

“…The former three oligonucleotides were synthesized based on the sequences of the protein coding regions in rice chloroplast DNA [15] and the latter three based on wheat chloroplast DNA sequence [30]. These oligonucleotides were labelled at their 5' ends with [TYP]ATP and T4 polynucleotide kinase.…”

“…Transcript from the psbE operon It has been found in various plants that genes coding psbE, psbF, psbL and psbJ form a cluster and are co-transcribed as a single transcript [7,30,32]. Northern hybridization was carried out using psbE, psbF, psbL and psbJ probes independently for the plastid RNAs from 5-day old dark-grown wheat seedlings before and after transfer to light.…”

An open reading frame encoding a putative haem-binding polypeptide is contranscribed with the pea chloroplast gene for apocytochrome f

“…Although the photosynthetic apparatus of higher plants is fairly well characterised [ 14], the identification in the past year or so of several chloroplast genes encoding small polypeptides of photosystem II [22,23,29,43,44] and the cytochrome bf complex [15] indicates that further genes for photosynthesis components may be present in chloroplast DNA. Little, or nothing, is known about the constituent polypeptides of ion transport systems in the thylakoid membrane [ 18,36,38] or transporters in the chloroplast envelope [ 16].…”

Differential accumulation of plastid transcripts encoding photosystem II components in the mesophyll and bundle-sheath cells of monocotyledonous NADP-malic enzyme-type C4 plants

“…The relative transcript levels of plastid-encoded PSII genes in mesophyll and bundle- Bedbrook et al 1978;Zurawski et al 1982Westhoff et al 1983Herrmann 1984 Westhoff et al 1983;Alt et al 1984;Holschuh et al 1984Rochaix et al 1984Herrmann et al 1984Westhoff et al 1985bHerrmann et al 1984Hird et al 1986Westhoff et al 1986Ikeuchi and Inoue 1988;Webber et al 1989bMurata et al 1988Webber et al 1989a psbA, the psbE/F gene cluster, the psbB and psD/C operons. The assignment of transcripts is based on: psbA: (Zurawski et al 1982); psbB operon: (Rock et al 1987;Barkan 1988;Westhoff et al 1990); psbD/C operon (Berends et al 1987;Gamble et al 1988;Offermann 1988;Yao et al 1989); psbE/F; (Westhoff et al 1985b;Webber et al 1989a;Westhoff et al 1990). The positions of RNA 5' and 3' termini are marked by black and white triangles, respectively.…”