XB-IMG-135667
Xenbase Image ID: 135667
|
Expression of ESR-4 and ESR-5 inXenopus embryos. (A–D) Xenopus embryos at different stages were stained for the expression of ESR-4 andESR-5 with whole-mount, in situ hybridization. All embryos are oriented in this figure as in subsequent figures with anterior to the left. (A) Expression of ESR-5 at late gastrulae stage (st. 12, dorsal view), (B) at early neurulae stage (st. 14/15, dorsal view), and (C) at late neurulae stage (st. 22/24, side view). (D) Expression ofESR-4 at late neurulae stage (st. 22/24, side view). Note that the expression patterns of both ESR-4 andESR-5 at these different stages consists of a TBD, and two stripes that lie anterior to the TBD in somitomere 1(S1) and 2(S2). The expression patterns of ESR-4 and ESR-5 differ only in one respect: The TBD staining for ESR-5 is more intense and tends to extend more rostrally than that of ESR-4. (C,D; also see Fig. C,I). (E–G) Three examples ofESR-5 staining taken from a batch of embryos processed at stage 22. Side views of the posterior third of the embryos are shown. The asterisk marks what appears to be the emergence of a gap in the TBD expression of ESR-5 in a region referred to as the TZ. (H–J) Double labeling of embryos with whole-mount in situ hybridization with probes for ESR-5 and X-Delta-2. (H) Embryo stained for X-Delta-2 alone with Magenta–Phos (MP) as the chromogen, (I) ESR-5 RNA alone with BCIP, or (J) both ESR- 5 with BCIP andX-Delta-2 with MP. Note that the ESR-5 staining in S1 overlaps with the S1 staining in X-Delta-2. (K) Diagram showing the position of ESR-4 and ESR-5expression relative to that of other genes known to be expressed segmentally in Xenopus embryos (Jen et al. 1997; Sparrow et al. 1998). Because cells are constantly being added posteriorly to the paraxial mesoderm and somites are constantly forming anteriorly, the stripes of gene expression in the somitomeric region represent transient expression in groups of cells as they pass through this domain. For this reason, the S1-4 notation in this and other figures does not denote a fixed group of cells along the AP axis, but rather to different stages of the segmentation process that cells pass through in the paraxial mesoderm. Image published in: Jen WC et al. (1999) Copyright © 1999. Image reproduced on with permission of the Publisher, Cold Spring Harbor Laboratory Press. This is an Open Access article. Larger Image Printer Friendly View |