Two interacting bZIP proteins are direct targets of COP1-mediated control of light-dependent gene expression in Arabidopsis.

By M. Holm, Li-geng Ma, Li-jia Qu, X. Deng. Genes & Development, 2002

611 citations recorded by the source corpus.

Arabidopsis COP1 acts to repress photomorphogenesis in the absence of light. It was shown that in the dark, COP1 directly interacts with the bZIP transcription factor HY5, a positive regulator of photomorphogenesis, and promotes its proteasome-mediated degradation. Here we identify a novel bZIP protein HYH, as a new target of COP1. We identify a physical and genetic interaction between HYH and COP1 and show that this interaction results in dark-specific degradation of HYH. Genetic analysis indicates that HYH is predominantly involved in blue-light regulation of development and gene expression, and that the function of HYH in part overlaps with that of HY5. The accumulation of HYH protein, not the mRNA, is dependent on the presence of HY5. Our data suggest that HYH and HY5 can, respectively, act as heterodimers and homodimers, thus mediating light-regulated expression of overlapping as well as distinct target genes. We propose that COP1 mediates light control of gene expression through targeted degradation of multiple photomorphogenesis-promoting transcription factors in the nucleus.

Subfields: Molecular Biology, Plant Science

View Paper: https://www.semanticscholar.org/paper/82bcc8c99fdb6661e53febe2d77efa306d66ebbb

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Molecular Biology

1. C. Fankhauser
2. Lorena Pizarro
3. C. Stange
4. Meng Chen
5. X. Deng
6. Mukesh Jain
7. Joanne Chory
8. Akhilesh K. Tyagi

In Plant Science

1. C. Fankhauser
2. Lorena Pizarro
3. C. Stange
4. Meng Chen
5. X. Deng
6. Joanne Chory
7. Akhilesh K. Tyagi
8. E. Schäfer

Citations in the corpus

• Phytochrome‐mediated photoperception and signal transduction in higher plants (2002, background): “COP1 can also interact with a number of other proteins (Hardtke and Deng, 2000) including putative transcription factors (e.g. Holm et al., 2002), and is thought to regulate their activity in a similar way to HY5.”
• Light signal transduction in higher plants. (2004, background): “They include HY5, which is required for de-etiolation under all light conditions; the HY5 homolog, HYH (HY5 Homologue), which is mainly required in blue light; and the bHLH protein HFR1 (long Hypocotyl in FR light), a component of both cryptochrome and phyA signaling (40, 77, 183).”
• Light-dependent regulation of carotenoid biosynthesis in plants (2009, background): “It has been shown that HY5 and HFR1 transcription factors co-localize with COP1 in nuclear bodies and are marked for post-translational degradation during repression of photomorphogenesis (Ang et al., 1998; Jung et al., 2005).”
• Light-regulated transcriptional networks in higher plants (2007, background): “Adding a further level of complexity to the regulation of transcription in response to light, certain light-regulated transcription factor families tend to form dimers, such as bHLH (basic helix–loop–helix) and bZIP (basic leucine zipper) familie”
• Functional Analysis of the RING-Type Ubiquitin Ligase Family of Arabidopsis1[w] (2005, background): “E2-dependent ubiquitin ligase activity has been demonstrated and targets identified for only a few RING proteins, including RMA1, PRT1, COP1, CIP8, and SINAT5 (Matsuda et al., 2001; Hardtke et al., 2002; Holm et al., 2002; Xie et al., 2002; Stary et al., 2003).”
• Genomic Survey and Gene Expression Analysis of the Basic Leucine Zipper Transcription Factor Family in Rice1[W][OA] (2007, background): “Vol. 146, 2008 the Arabidopsis bZIP proteins like HY5 and HYH interact with the WD40 domain of COP1 (Holm et al., 2001, 2002).”