Xenbase Image ID: 156875

FIG. 1. The X. tropicalis slug promoter is inefficient in X. laevis embryos. A, constructs containing different fragments of the X. tropicalis slug promoter (Prom Xt Slug) were injected into X. laevis embryos (upper panel). GFP expression was detected by RT-PCR performed on stage 19 NF embryos (middle panel). Histone H4 was used as an internal control for semiquantitative analysis (lower panel). The bars indicate the means S.D. of three independent experiments. Negative control lanes of the gel correspond to samples where no reverse transcriptase was added. The p200-GFP and p3900-GFP constructs gave the strongest expression. B, to compare the efficiency of the X. tropicalis slug promoter with that of the endogenous promoter, a modified X. laevis Slug cDNA was inserted downstream from the p200 and p3900 promoters (upper panel). With a single set of primers (U and D), both endogenous (endo) and exogenous (exo) Slug cDNAs were amplified (middle panel). This made it possible to compare mRNA levels (lower panel). The relative amount of exogenous product was much lower than expected with the Sleeping Beauty expression system, indicating that the X. tropicalis slug promoter is inefficient in X. laevis embryos. a.u., arbitrary units; u, uninjected; St, stage. Image published in: Vallin J et al. (2001) Copyright © 2001. 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. Larger Image Printer Friendly View

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