Figure 2.

Fxr1p is conserved in vertebrates. (a) Detection of xFxr1 mRNA variants by RT-PCR in different tissues from mouse and frog by using primers flanking the muscle-specific exon. Northern blots containing RNA isolated from murine and frog tissues (H, heart; B, brain; M, muscle; L, liver; and K, kidney) were hybridized with probes specific for mouse and frog Fxr1. The muscle sequence (exon 15) is found in both mouse and Xenopus. (b) Amino acid sequence of Xenopus Fxr1p (xFxr1p) aligned with human (hFXR1P), mouse (mFxr1p), and zebrafish (zFxr1p) sequences. Conserved amino acids are boxed in black, similar amino acids are in light gray and divergent amino acids are in white. (c) Representation of the mouse (m Iso a-g) and Xenopus (x Iso a and b) Fxr1 mRNA-spliced variants.