Survivin increased vascular development during Xenopus ontogenesis.

Area of Science:

• Developmental biology
• Cell biology
• Cancer research

Background:

• Survivin, an inhibitor of apoptosis protein (IAP) family member, has known anti-apoptotic and proliferative roles.
• Mammalian Survivin is typically absent in adult tissues but highly expressed in human cancers.
• Its function during development remains less understood.

Purpose of the Study:

• To investigate Survivin expression and function during vertebrate development using the Xenopus model.
• To characterize the evolutionary conservation and duplication of Survivin genes across species.
• To elucidate the specific mechanisms underlying Survivin's role in vascular development.

Main Methods:

• Comparative genomics to identify Survivin genes in various vertebrate species.
• Utilizing the Xenopus laevis developmental model for gene expression studies.
• Generating transgenic Xenopus to study the functional impact of Survivin (Su1) expression.

Main Results:

• Two distinct Survivin genes (Su1 and Su2) were identified in amphibians and fish, unlike the single gene in mammals.
• Xenopus Su1 exhibits differential spatiotemporal transcription during development.
• Transgenic Su1 expression in tadpoles resulted in enlarged blood vessels due to increased endothelial cell proliferation, dependent on its BIR domain and phosphorylation site.

Conclusions:

• The Survivin gene has undergone duplication in non-mammalian vertebrates.
• Xenopus Su1 plays a crucial role in promoting blood vessel development through endothelial cell proliferation.
• This vascular-promoting function of Su1 is distinct from its canonical anti-apoptotic activity.