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FIGURE 1. Expression pattern of hspa5 in developing Xenopus embryos. A–K, spatial expression pattern of hspa5 analyzed by whole mount in situ hybridization.
Embryos are shown in different views (dorsal-lateral and vegetal). A and B, Hspa5 was expressed in the animal half prior to gastrulation stages. C–E,
during gastrulation, hspa5 is strongly expressed in ventral ectoderm, dorsal blastopore lip, and the developing notochord but is absent from the prospective
neural plate. In C and D, the red arrow indicates dorsal blastopore lip; in E, the white arrowhead indicates the notochord. F and G, at neurula stages, hspa5
expression is restricted to the notochord (white arrow) and the region anterior to the neural plate (red arrow) that corresponds to the future cement gland. H
and I, at stage 22, strong expression is found in the cement and hatching glands. H, anterior view; I, lateral view. J and K, at the tail bud stage, hspa5 is expressed
in the cement gland, pronephros (red arrow), ear vesicle, and epidermis. It is notable that the hspa5 signal can also be found in the liver primordium (K, black
arrow). L andM, transverse sections of tail bud stages (J) showing hspa5 expression in pronephros (pn) and notochord (nc) tissue. N and O, transverse sections
of a late tail bud stage embryo (K) show hspa5 expression in the pronephros (pn) and liver (li). P–S, Xbp1 expression in Xenopus embryos at the stages indicated.
T, RT-PCR shows the temporal expression pattern of hspa5. Numbers above the lanes indicate the corresponding embryonic stages. A negative control (RT )
without reverse transcriptase was included. odc expression was used as the internal standard control. U, schematic diagram illustrating the interaction of Xbp1
and Hspa5 in the unfolded protein response. V, real time PCR indicates that hspa5 is up-regulated by overexpression of xbp1. xbp1mRNAat the indicated doses
was injected into Xenopus embryos at the two-cell stage. Animal caps were dissected at stage 9 and cultured for 2 h. The expression of hspa5 was analyzed by
real time PCR, and its expression was normalized to odc. The animal cap assay was performed twice. St, stage. |
