Fig. 5. ref-2 encodes a protein with five zinc-finger domains similar to the opa/Zic family of zinc-finger genes. (A) The region around the mu218 GA transition is depicted. The mutation lies 399 bp beyond the last base in the 3' UTR listed in B. (B) Sequence and inferred translation of ref-2 cDNA determined by sequencing of RT-PCR products. The five C₂H₂ zinc finger domains are underlined. The location of introns is indicated by black triangles. A putative polyadenylation signal is underlined twice. (C) Alignment of the zinc-finger region of REF-2 with the zinc finger region of the related proteins Xenopus Zic2 (Nakata et al., 1998), human ZIC1 (Yakota et al., 1996), mouse Zic3 (Aruga et al., 1996) and Drosophila Opa (Benedyk et al., 1994; Cimbora and Sakonju, 1995). Residues conserved in at least 50% of sequences are highlighted in black. Asterisks below the sequences indicate the conserved cysteines and histidines. Data analysis was carried out using Pileup and Boxshade (GCG Wisconsin Package version 10.1, Genetics Computer Group, Madison, WI).