2020 Ph.D. Admissions (Interview List)

Friday Seminar by Mr. Aishwarye Sharma

JPK Lab/ December 27, 2019/ Friday/ 3.30 pm/ B-box proteins: some new insights
Category: Research
Posted by: bedineel


B-box proteins: Some new insights


Transcription factors play important role in plant growth and development. B-box proteins are zinc-finger transcription factors that possess  one or two B-Box domains, along with or without a CCT domain. Initially, the knowledge of the role of BBX proteins was limited to regulation of reproductive development (CONSTANS and CONSTANS-LIKE) and photomorphogenesis (BBX21, BBX24 etc.). Many of the B-box proteins work synergistically or antagonistically with HY5 and COP1, playing important role in fine-tuning of photomorphogenesis. Interestingly, BBX28 has been found to interact with HY5 in light conditions and interfere its binding to its target genes, acting as a negative regulator of photomorphogenesis. However, BBX28 itself is degraded in the dark by COP1 like other positive regulators of photomorphogenesis. Recently, new studies have reported diverse functions of BBX proteins. BBX19 has been reported to  bind to GT1 motifs in the promoter region of an ABA signaling regulator ABI5, and induce its expression that results in inhibition of seed germination. In another study, BBX18 and BBX23 has been reported to regulate thermomorphogenesis. The two proteins promotes PIF4 expression by interacting with ELF3 and COP1 and help in ELF3 degradation, which is a negative regulator of thermomorphogenesis. These studies indicate that B-box proteins act as check-points that regulate diverse functions in plants.


  • Lin, F., Jiang, Y., Li, J., Yan, T., Fan, L., Liang, J., Chen, Z.J., Xu, D. and Deng, X.W., 2018. B-BOX DOMAIN PROTEIN28 negatively regulates photomorphogenesis by repressing the activity of transcription factor HY5 and undergoes COP1-mediated degradation. The Plant Cell, 30(9), pp.2006-2019.
  • Bai, M., Sun, J., Liu, J., Ren, H., Wang, K., Wang, Y., Wang, C. and Dehesh, K., 2019. B‐box protein BBX 19 suppresses seed germination via induction of ABI 5. The Plant Journal.
  • Ding, L., Wang, S., Song, Z.T., Jiang, Y., Han, J.J., Lu, S.J., Li, L. and Liu, J.X., 2018. Two B-Box Domain Proteins, BBX18 and BBX23, Interact with ELF3 and Regulate Thermomorphogenesis in Arabidopsis. Cell reports, 25(7), pp.1718-1728.