Cry2, or Cryptochrome 2, is a gene with diverse functions. In plants, it serves as a blue-light photoreceptor regulating various growth aspects. In mammals, it is a core circadian clock regulator and is also involved in processes like DNA damage repair. It participates in multiple pathways, such as those related to plant growth, adipogenesis, and circadian rhythm regulation, and is of great biological importance [1-10].

In plants, Arabidopsis studies show that Cry2 affects the transcriptome even in darkness, suppressing cell division in the root apical meristem to inhibit root elongation in the dark, while blue-light oligomerizes Cry2 to de-repress root elongation. It physically interacts with FORKED-LIKE 1 (FL1) and FL3 in darkness to inhibit their pro-growth activity on cell division genes [1]. In Arabidopsis, Cry2 is also involved in blue-light-dependent cold acclimation through the CRY2-COP1-HY5-BBX7/8 module, and in thermosensory flowering via interaction with CIS1 to regulate FLM alternative splicing [2,4].

In mammals, in vitro and in vivo studies on adipogenesis demonstrate that Cry2 promotes adipocyte development by repressing the Wnt pathway through interaction with Per2. Mutations in Cry2 in mouse models can accelerate the growth of primary mouse fibroblasts expressing high levels of c-MYC and suppress P53 target-gene expression [5-7]. In 5xFAD mice, overexpression of Cry2 leads to decreased cognitive function, while down-regulation attenuates sleep-deprivation-induced cognitive decline, as Cry2 reduces CISH-mediated STAT1 phosphorylation resulting in synaptic dysfunction [3].

In conclusion, Cry2 plays essential roles in plant growth, including root elongation, cold acclimation, and thermosensory flowering. In mammals, it is involved in adipogenesis, cell growth regulation, and cognitive function related to sleep deprivation. The use of genetic models, such as Arabidopsis in plant studies and mouse models in mammalian research, has significantly contributed to understanding Cry2's functions in these biological processes and disease-related conditions.

References:

1. Zeng, Desheng, Lv, Junqing, Li, Xu, Liu, Hongtao. 2024. The Arabidopsis blue-light photoreceptor CRY2 is active in darkness to inhibit root growth. In Cell, 188, 60-76.e20. doi:10.1016/j.cell.2024.10.031. https://pubmed.ncbi.nlm.nih.gov/39549699/

2. Li, Youping, Shi, Yiting, Li, Minze, Liu, Hongtao, Yang, Shuhua. . The CRY2-COP1-HY5-BBX7/8 module regulates blue light-dependent cold acclimation in Arabidopsis. In The Plant cell, 33, 3555-3573. doi:10.1093/plcell/koab215. https://pubmed.ncbi.nlm.nih.gov/34427646/

3. Luo, Sumei, Guo, Lizhe, Chen, Na, Wang, Yunjiao, Wang, E. 2024. CRY2 mediates the cognitive decline induced by sleep deprivation in 5xFAD mice. In PloS one, 19, e0306930. doi:10.1371/journal.pone.0306930. https://pubmed.ncbi.nlm.nih.gov/39012854/

4. Zhao, Zhiwei, Dent, Craig, Liang, Huafeng, Balasubramanian, Sureshkumar, Liu, Hongtao. 2022. CRY2 interacts with CIS1 to regulate thermosensory flowering via FLM alternative splicing. In Nature communications, 13, 7045. doi:10.1038/s41467-022-34886-2. https://pubmed.ncbi.nlm.nih.gov/36396657/