CLV3CLV1WUS

CLV3CLV1WUS refers to the core regulatory module of the CLAVATA-WUSCHEL network that maintains stem cells in the shoot apical meristem (SAM) of flowering plants, especially Arabidopsis thaliana. This network centers on the interaction between the WUSCHEL transcription factor, the CLAVATA3 peptide, and the receptor components that perceive CLV3 signaling.

Key components and roles:

- WUSCHEL (WUS): a homeobox transcription factor expressed in the organizing center beneath the stem cell layer. WUS promotes stem cell identity and activates CLV3 expression in the overlying cells.

- CLAVATA3 (CLV3): a small secreted peptide produced by stem cells. It forms part of a signaling gradient that feeds back to limit WUS activity and thereby constrain the size of the stem cell pool.

- CLAVATA1 (CLV1) and CLAVATA2 (CLV2): receptor-like kinases and associated co-receptors that perceive CLV3 signaling. The CLV3 signal is transmitted through a receptor complex that includes CLV1 and CLV2, leading to repression of WUS activity or expression.

Mechanism and significance:

WUS activity in the organizing center sustains the SAM and induces CLV3 expression in the outer cell layers. CLV3 peptide signaling through the CLV1-CLV2 receptor complex inhibits WUS, forming a negative feedback loop. This loop balances stem cell renewal with differentiation, ensuring proper SAM size and organ formation. Mutants in CLV3, CLV1, or CLV2 typically exhibit enlarged SAMs and extra floral organs, whereas wus mutants show reduced or terminated SAMs. The CLV-WUS pathway exemplifies how short-range signaling maintains stem cell populations in plants and has become a foundational model in plant developmental biology and agricultural biotechnology.