XB-ART-4722Mech Dev 2003 Aug 01;1208:937-48. doi: 10.1016/s0925-4773(03)00162-x.
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A homologue of cysteine-rich secretory proteins induces premature degradation of vitelline envelopes and hatching of Xenopus laevis embryos.
We cloned Xenopus laevis CRISP, XCRISP, a homologue of the mammalian family of cysteine-rich secretory proteins (CRISPs), which has been previously identified as a Wnt3a/noggin responsive gene in an expression screen [Mech. Dev. 87 (1999) 21]. We detected XCRISP expression exclusively in the hatching gland. XCRISP enters the secretory pathway and accumulates on the surface of presumptive hatching gland cells. Overexpression studies of XCRISP and XCRISP-mutants show that XCRISP induces premature hatching of embryos preceded by degradation of the vitelline envelope. A deletion mutant that lacks a 35 amino acid domain even accelerates hatching, while further deletion of the carboxy-terminus reverses these effects. From our studies, we conclude that XCRISP is sufficient to induce degradation of vitelline envelopes and that this activity maps to the most C-terminal amino acids, while the adjacent domain regulates XCRISP activity.
PubMed ID: 12963113
Article link: Mech Dev
Species referenced: Xenopus laevis
Genes referenced: ag1 crisp1.6
Article Images: [+] show captions
|Fig. 2. XCRISP is expressed in the hatching gland. At stage 17 (A) the XCRISP positive cells are co-localised with XAG in two stripes outlining the neural plate. In later neurula, stages 23 (B) and 28 (C), with closure of the neural tube the two lines of hatching gland cells converge to a y-shaped pattern. XAG staining is overlaid by XCRISP, but visible in the XCRISP-negative cement gland (red). Expression of XCRISP persists till stage 32 (D) when still positive cells are detected in a shorter y-pattern on the head of the embryos. XCRISP expressing cells are detected in two patches directly on top of the neural tube in stage 23 (E), in stage 28 the two separate groups of cells have fused to a single structure (F). The temporal expression profile is confirmed by RT-PCR, which detects XCRISP from stage 19 to 35 (G).|