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Gene Review

psbD  -  photosystem II protein D2

Arabidopsis thaliana

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Disease relevance of psbD

  • Expression of a higher-plant chloroplast psbD promoter in a cyanobacterium (Synechococcus sp. strain PCC7942) reveals a conserved cis-element, designated PGT, that differentially interacts with sequence-specific binding factors during leaf development [1].
  • The recombinant SIG2 protein mixed with Escherichia coli core RNA polymerase could bind to a DNA fragment that contains the SIG2-dependent psbD -256, trnE-UUC or trnV-UAC promoter [2].

High impact information on psbD

  • The reaction center core of photosystem II is composed of two chlorophyll binding proteins, D1 and D2, that are encoded by the chloroplast genes psbA and psbD [3].
  • Therefore, cry1/cry2/phyA-mediated blue light activation of the psbD light-responsive promoter in 21-day-old Arabidopsis plants does not involve hy5, a transcription factor that mediates other phyA and blue light-induced responses [3].
  • In this study, light-activated chloroplast and psbD transcription were studied after dark adaptation of 21-day-old light-grown Arabidopsis plants [3].
  • The plastid psbD gene encoding the photosystem II reaction center protein D2 is under the control of a unique blue light responsive promoter (BLRP) that is transcribed by a bacterial-type plastid RNA polymerase (PEP) [4].
  • Furthermore, transient overexpression of AtSig5 in dark-adapted protoplasts specifically elevated psbD and psbA transcription activities [4].

Biological context of psbD

  • In the chloroplast psbD light-responsive promoter (LRP), a highly conserved sequence exists upstream from the bacterial -10/-35 elements [5].
  • Using yeast one-hybrid screening of an Arabidopsis cDNA library, a possible DNA binding protein of the psbD LRP upstream sequence was identified [5].
  • On the other hand, overproduction of AtSig2 enhanced the transcription of psbA gene and trnE operon, but not psbD transcription [4].
  • Interestingly, transcription from the psbD blue light-responsive promoter (psbD-BLRP) was activated by not only light but also various stresses, and the transcription and the transcriptional activation of psbD-BLRP were abolished in a sig5-2 mutant [6].
  • Nucleotide sequences within this region are conserved among the psbD genes of several monocots and dicots, and with the nuclear negative regulatory element GT [1].

Regulatory relationships of psbD

  • A model is proposed involving blue light, DET1 and phytochrome in regulating transcription from the psbD BLRP [7].

Other interactions of psbD

  • These results suggest that PTF1 is a trans-acting factor of the psbD LRP [5].
  • Transcription from the Arabidopsis psbD promoter was 3-fold higher in blue relative to red light, whereas red and blue light affected total chloroplast, rbcL, and 16S rDNA transcription similarly [8].
  • It has recently been shown in barley seedlings that activation of psbD-psbC transcription by blue light involves inhibition of a protein kinase that represses the BLRP in the dark [7].
  • A T-DNA insertional mutant with reduced AtSIG5 expression resulted in loss of primary transcripts from the psbD BLRP [4].
  • The lack of destabilization of a second chloroplast encoded transcript, psbD, indicates that the phot1/B-high-fluence system does not result in a general destabilization of all chloroplast transcripts [9].


  1. Expression of a higher-plant chloroplast psbD promoter in a cyanobacterium (Synechococcus sp. strain PCC7942) reveals a conserved cis-element, designated PGT, that differentially interacts with sequence-specific binding factors during leaf development. Christopher, D.A., Shen, Y., Dudley, P., Tsinoremas, N.F. Curr. Genet. (1999) [Pubmed]
  2. Molecular genetic analysis of chloroplast gene promoters dependent on SIG2, a nucleus-encoded sigma factor for the plastid-encoded RNA polymerase, in Arabidopsis thaliana. Hanaoka, M., Kanamaru, K., Takahashi, H., Tanaka, K. Nucleic Acids Res. (2003) [Pubmed]
  3. Cryptochrome 1, cryptochrome 2, and phytochrome a co-activate the chloroplast psbD blue light-responsive promoter. Thum, K.E., Kim, M., Christopher, D.A., Mullet, J.E. Plant Cell (2001) [Pubmed]
  4. Blue light-induced transcription of plastid-encoded psbD gene is mediated by a nuclear-encoded transcription initiation factor, AtSig5. Tsunoyama, Y., Ishizaki, Y., Morikawa, K., Kobori, M., Nakahira, Y., Takeba, G., Toyoshima, Y., Shiina, T. Proc. Natl. Acad. Sci. U.S.A. (2004) [Pubmed]
  5. Involvement of a nuclear-encoded basic helix-loop-helix protein in transcription of the light-responsive promoter of psbD. Baba, K., Nakano, T., Yamagishi, K., Yoshida, S. Plant Physiol. (2001) [Pubmed]
  6. The multiple-stress responsive plastid sigma factor, SIG5, directs activation of the psbD blue light-responsive promoter (BLRP) in Arabidopsis thaliana. Nagashima, A., Hanaoka, M., Shikanai, T., Fujiwara, M., Kanamaru, K., Takahashi, H., Tanaka, K. Plant Cell Physiol. (2004) [Pubmed]
  7. DET1 represses a chloroplast blue light-responsive promoter in a developmental and tissue-specific manner in Arabidopsis thaliana. Christopher, D.A., Hoffer, P.H. Plant J. (1998) [Pubmed]
  8. Structure and blue-light-responsive transcription of a chloroplast psbD promoter from Arabidopsis thaliana. Hoffer, P.H., Christopher, D.A. Plant Physiol. (1997) [Pubmed]
  9. Phototropin 1 is required for high-fluence blue-light-mediated mRNA destabilization. Folta, K.M., Kaufman, L.S. Plant Mol. Biol. (2003) [Pubmed]
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