XB-IMG-74598
Xenbase Image ID: 74598
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Fig. 5.
Injections of cer-S mRNA dose-dependently reduce Xbra expression in gastrula embryos. Embryos are injected radially in the vegetal pole at the 4 cell stage, then processed for Xbra in situ staining at stage 10.5. (A) Control uninjected embryo, Xbra is expressed as a mesodermal ring. (B-E) Embryos injected with increasing amounts of cer-S mRNA, showing graded reduction of the Xbra expression domain. (F) Embryos injected vegetally with 400 pg of cer- S mRNA at the 4-cell stage and with lacZ lineage tracer mRNA into blastomere C4 at the 32- cell stage. In this lateral view the white arrowhead indicates lacZ in the ventral side (note that the pigment in the animal cap also marks the ventral side) and the black arrowhead points to the expression of Xbra transcripts on the dorsal side (n=51). (G) RT-PCR analysis of Xenopus embryos injected with 600 pg of cer-S mRNA. RNAs were harvested from uninjected controls or cer-S-injected embryos at one-hour intervals at stages 8.5 (lanes 1, 2), 9.0 (lanes 3, 4) and 9.5 (lanes 5, 6). Xnr1, 2 and 4 transcripts are initially not inhibited by cer-S (lanes 1, 2), but are decreased at later stages (a positive feedback loop for Nodal-related gene expression has been described; Meno et al., 1999). Importantly, the levels of derrière, Vg1, VegT and Xnr3 remained unchanged, and activin βB was only partially decreased. Note that cer-S mRNA inhibited the initial expression of Xbra and that cer-S can inhibit Xbra transcriptional activation even in the presence of derrière, activin and Vg1 transcripts. Image published in: Agius E et al. (2000) Copyright © 2000. Image reproduced with permission of the publisher and the copyright holder. This is an Open Access article distributed under the terms of the Creative Commons Attribution License.
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