BEND2 is a protein that in humans is encoded by the BEND2 gene. It is also found in other vertebrates, including mammals, birds, and reptiles. The expression of BEND2 in Homo sapiens is regulated and occurs at high levels in the skeletal muscle tissue of the male testis and in the bone marrow. The presence of the BEN domains in the BEND2 protein indicates that this protein may be involved in chromatin modification and regulation. Gene Common aliases BEND2 stands for BEN domain containing 2 and is also known as CXorf20 (HGNC ID: 28509). Locus and size The locus for BEND2 is on the minus strand of the X chromosome at Xp22.13. The gene is approximately 58 kilobases in length. mRNA Alternative splicing BEND2 contains 14 exons which undergo alternative splicing to create five transcript variants that vary from 4,720 base pairs (bp) to 2,144 bp in the mature mRNA. The longest and most complete transcript of the gene, variant 1, encodes isoform 1 of the BEND2 protein (NP_699177.2). 5' and 3'UTR The untranslated regions (UTR) flanking the coding sequence of BEND2 at the 5' and 3' end of the mature mRNA molecule contain sites for RNA-binding proteins, including RBMX, pum2, and EIF4B as well as microRNA binding sites. The 5'UTR also contains an upstream in-frame stop codon and the 3'UTR contains a polyadenylation signal sequence. Protein (Isoform 1) Molecular weight and internal composition The predicted molecular weight is 87.9 kDal. The predicted isoelectric point is pH 5.07. The internal composition is enriched for serine residues. Isoforms Corresponding to the five alternative transcripts of BEND2, the protein encoded by this gene is found in two isoforms (1 and 2) as well as three predicted structures (X1, X2, and X3). These isoforms range from 813 to 645 amino acids in length. Isoform 1 is 799 amino acids in length. Subcellular location The presence of nuclear localization signals within the amino acid sequence or primary structure of the BEND2 protein leads to a prediction of subcellular localization in the nucleus. The pat7 [(P-X(1-3)-(3-4K/R)] signal and a nuclear bipartite signal are both found near the N-terminus of the protein. Structure The secondary structure for BEND2 is unclear, in particular at the N-terminus, which is poorly conserved between orthologs. The C-terminus contains two BEN domains, which are predicted to form a series of alpha helices. Post-translational modifications Based on its primary structure, BEND2 is