title: Molecular interactions of BBX24 and BBX25 with HYH, HY5 HOMOLOG, to modulate Arabidopsis seedling development.
abstract: BBX24 and BBX25 are two important transcriptional regulators, which regulate seedling photomorphogenesis in Arabidopsis. Very recently, we have shown that BBX24 and BBX25 negatively regulate the expression of BBX22, reducing the function of HY5, by physically interacting with its bZIP domain. (1) Furthermore, HY5 HOMOLOG, HYH, has been reported to heterodimerize with HY5 and enhances its photomorphogenic function in seedling de-etiolation by serving as coactivator. (8) Here, we further report that BBX24 and BBX25 physically interact with HYH. The physical interactions of BBX24 and BBX25 with HYH could lead to depletion of HYH molecules from the active pool and, thus indirectly, reduce the function of HY5 in promoting photomorphogenesis. Hence, our results suggest another mode of regulation by which BBX24 and BBX25 exert their negative effects on HY5 indirectly through HYH for the fine-tuning of seedling photomorphogenesis.
authors.affiliation: Department of Biological and Environmental Sciences; Gothenburg University; Gothenburg, Sweden; Current affiliation: Department of Biotechnology; National Institute of Technology; Durgapur, West Bengal, India.
authors.forename: Sreeramaiah N
authors.initials: SN
authors.lastname: Gangappa
authors.forename: Magnus
authors.initials: M
authors.lastname: Holm
authors.forename: Javier F
authors.initials: JF
authors.lastname: Botto
mesh_terms: D017360:Arabidopsis / Q000254:growth & development* / Q000378:metabolism; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000378:metabolism*; D050976:Basic-Leucine Zipper Transcription Factors / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D004268:DNA-Binding Proteins; D008954:Models, Biological; D009687:Nuclear Proteins / Q000378:metabolism*; D011485:Protein Binding; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D036226:Seedlings / Q000254:growth & development* / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D029681:Arabidopsis Proteins; C585246:BBX24 protein, Arabidopsis; C585245:BBX25 protein, Arabidopsis; D050976:Basic-Leucine Zipper Transcription Factors; D002352:Carrier Proteins; D004268:DNA-Binding Proteins; C109254:HY5 protein, Arabidopsis; C457459:HYH protein, Arabidopsis; D009687:Nuclear Proteins; D012097:Repressor Proteins; D014157:Transcription Factors
keywords: BBX; HY5; HYH; de-etiolation; light