Fig. 2.

The role of SAG in the development of embryonic organ system. Under the stimulation of ROS, mitogen and hypoxia environment, SAG transcription was induced by AP-1and HIF-1. SAG proteins can recruit other components of CRL to boost ubiquitination and degrade various substrates, including P27, C-Jun, IκBα and HIF-1α, etc. Without SAG, those proteins cannot be ubiquitinated and affect the process of EMT, degradation and apoptosis, causing angiogenesis defects and even embryonic death