Fig 6. Prx-Cre1-mediated recombination of the Ubr5^gt and loss of Ubr5 expression.

Prx1-Cre promotes UBR5^MT-associated β-Gal activity (A-E), lacZ expression (F) and (G) loss of Ubr5 expression. (A-C) E13.5 embryos of the indicated genotypes stained for β-Gal activity revealed strong X-Gal staining in the embryonic limbs, in addition to other regions: above the eye, white arrow; the ear, black arrow; snout black arrowhead and head, white arrowhead. Scale bar = 1mm. (D-E) Histological sections through the footplate revealed a non-uniform UBR5^MT expression pattern (red dashed lines = chondrocyte condensations; white dashed lines = dark staining mesenchyme and red dotted line = developing sinews). Scale bar = 250μm. qRT-PCR analysis of (F) LacZ expression and (G) full-length Ubr5 in dissected E13.5 fore- and hind-limb buds. Prx1-Cre in combination with heterozygosity or homozygosity for the Ubr5^mt* allele exhibited (F) a dramatic increase in LacZ expression and (G) a dramatic decrease in Ubr5 expression in comparison to Prx1-Cre only (Con). The primer pairs in (G) were specific for a gene region absent in the Ubr5^mt* transcript. All differences relative to the appropriate Prx1-Cre controls (Con) were statistically significant (at least p = <0.05), apart from the comparison between Con and Ubr5^mt*/mt*, which was not significant (ns). n = ≥3, s.e.m indicated. Statistical analysis by one-way ANOVA and Tukey multiple comparison test.