Figure 1. Embryonic expression of Psf2. A: An example of a whole mount in situ hybridization pattern showing localization of Psf2 in specific embryonic tissues (stage 33) is shown. Note the expression in the brain (labeled as cns), the retina and lens of the eye (labeled as eye), mesoderm of the pharyngeal arches (labeled as pa), and in stripes representing a reiterated subset of the paraxial (somitic) mesoderm (labeled as pm). B: RT–PCR analysis of Xenopus laevis Psf2 at different stages of embryogenesis, as noted (all stages follow those of [15]). A portion of 1 kb ladder was run for reference (labeled as 1kb). The 1018 bp and 506 bp bands are labeled. Expected Psf2 PCR product is 577 bp. For simplicity, positive and negative control lanes are not shown here.