Bbx, short for bobby sox homolog, is a transcription factor encoding zinc finger protein. Bbx proteins are key factors in regulatory networks controlling various plant growth and developmental processes, including seedling photomorphogenesis, photoperiodic regulation of flowering, shade avoidance, and responses to biotic and abiotic stresses [1,2,3,4,5,7,8,9]. They are involved in light and hormonal regulation pathways in plants [3,4,5]. In animals, Bbx is related to phosphate homeostasis [6].

In mice, Bbx knockout (Bbx -/-) led to increased FGF23 expression, low phosphate levels in the serum, and skeletal abnormalities like low bone mineral density, reduced bone volume, and short and weak bones associated with low bone formation. Osteocyte-specific deletion of Bbx also resulted in similar phenotypes [6].

In conclusion, Bbx plays crucial roles in plants in growth, development, and stress responses, and in mice, it is essential for regulating phosphate homeostasis and bone development. The Bbx -/- mouse model has provided valuable insights into the role of Bbx in bone-related conditions.

References:

1. Talar, Urszula, Kiełbowicz-Matuk, Agnieszka. 2021. Beyond Arabidopsis: BBX Regulators in Crop Plants. In International journal of molecular sciences, 22, . doi:10.3390/ijms22062906. https://pubmed.ncbi.nlm.nih.gov/33809370/

2. Yang, Ning, Cong, Qing, Cheng, Longjun. . [BBX transcriptional factors family in plants-a review]. In Sheng wu gong cheng xue bao = Chinese journal of biotechnology, 36, 666-677. doi:10.13345/j.cjb.190302. https://pubmed.ncbi.nlm.nih.gov/32347061/

3. Bandara, Wathsala W, Wijesundera, W S S, Hettiarachchi, Chamari. 2022. Rice and Arabidopsis BBX proteins: toward genetic engineering of abiotic stress resistant crops. In 3 Biotech, 12, 164. doi:10.1007/s13205-022-03228-w. https://pubmed.ncbi.nlm.nih.gov/36092969/

4. Cao, Jing, Yuan, Jiale, Zhang, Yingli, Niu, Rui, Lin, Fang. 2023. Multi-layered roles of BBX proteins in plant growth and development. In Stress biology, 3, 1. doi:10.1007/s44154-022-00080-z. https://pubmed.ncbi.nlm.nih.gov/37676379/

5. Gangappa, Sreeramaiah N, Botto, Javier F. 2014. The BBX family of plant transcription factors. In Trends in plant science, 19, 460-70. doi:10.1016/j.tplants.2014.01.010. https://pubmed.ncbi.nlm.nih.gov/24582145/

6. Lee, Su Jeong, Kim, Ju Ang, Ihn, Hye Jung, Kim, Jung-Eun, Park, Eui Kyun. 2024. The transcription factor BBX regulates phosphate homeostasis through the modulation of FGF23. In Experimental & molecular medicine, 56, 2436-2448. doi:10.1038/s12276-024-01341-9. https://pubmed.ncbi.nlm.nih.gov/39482539/

7. Xuefen, Du, Wei, Xiaohong, Wang, Baoqiang, Xian, Wang, Jincheng, Luo. 2022. Genome-wide identification and expression pattern analysis of quinoa BBX family. In PeerJ, 10, e14463. doi:10.7717/peerj.14463. https://pubmed.ncbi.nlm.nih.gov/36523472/

8. Sarmiento, Felipe. 2013. The BBX subfamily IV: additional cogs and sprockets to fine-tune light-dependent development. In Plant signaling & behavior, 8, e23831. doi:10.4161/psb.23831. https://pubmed.ncbi.nlm.nih.gov/23425851/

9. Chang, Yingying, Sun, Haoyuan, Liu, Shiyu, Li, Mingjun, Zhao, Xiting. 2023. Identification of BBX gene family and its function in the regulation of microtuber formation in yam. In BMC genomics, 24, 354. doi:10.1186/s12864-023-09406-1. https://pubmed.ncbi.nlm.nih.gov/37365511/