Xenbase Image ID: 132637

FIG. 3. Earlier treatment of embryos with RA results in further expansion of the GATA-4 transcript pattern. (a) Embryos were analyzed (and are oriented) as in Fig. 1a (except that the embryos were fixed at stage 30) for GATA-4 (left) or Nkx2.5 (right) transcripts following continuous treatment of RA added at stage 10.5 (top), stage 14 (2nd from top), or stage 20 (3rd from top). Embryos on the bottom were controls treated only with DMSO. Even in embryos with anterior truncations the GATA-4 gene is transcribed in an expanded region of the lateral plate. GATA-5 and GATA-6 were also transcribed in these embryos, but did not show such an obvious expansion of the pattern. (b) Cross sections are shown of embryos treated with RA beginning at stage 10.5 and analyzed for GATA-4 transcripts as in (a). Compared to the control embryos (left), the GATA-4 transcript pattern is enhanced and expanded in the RA-treated embryos (middle). To confirm the identity of the endoderm layer, embryos were also analyzed for transcripts from the Sox17a gene. This pattern was unaffected by RA treatment (not shown). Sections were taken either from an anterior (A) position (top) or from a more posterior (P) position caudal to the heart proper (bottom). (c) Embryos were treated with RA from stage 10.5 and RNA was harvested from embryos after 4 h (left lanes) or at the equivalent of stage 30 (right lanes) and analyzed for GATA-4 or control EF-1a transcript levels by semiquantitative RT/PCR. Consistent with the signals detected by in situ hybridization, the steady-state transcript levels for GATA-4 were increased 100% by RA treatment. Image published in: Jiang Y et al. (1999) Copyright © 1999. Image reproduced with permission of the Publisher, Elsevier B. V. Larger Image Printer Friendly View

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