CXXC5 gene structure and protein product (RINF). (A) The CXXC5 (RINF) gene localizes to chromosome 5q31.3. The gene starts 139 008 130 bp from pter and ends 139 043 651 bp from pter. It is oriented in plus strand direction and is 35.522 kb long. (B) Genomic organization of CXXC5 (RINF) gene. The gene is organized in 4 exons and 95% of the open reading frame is located in exon 3. A putative retinoic acid–responsive element (RARE) of direct repeat 2 (DR2) type is situated at −3116 bp upstream of the exon 1 transcription start site. (C) Predicted amino acid sequence of RINF according to one-letter amino acid representation. The open reading frame predicts a protein sequence of 322 amino acid residues and a theoretical molecular weight of 32.98 kDa (http://www.expasy.ch/tools/pi_tool.html). The zinc-finger domain is underlined in red. (D) Except the CXXC zinc finger domain, no conserved structural domain was found. An alignment of the CXXC motif of RINF protein with its human paralogs is presented. Amino acids that are invariant among CXXC motifs are in gray, and the conserved cysteine residues are in red. The consensus sequence for CXXC-type zinc-finger can be defined by Cx2Cx2Cx4-5Cx2Cx2C9-15Cx4C.