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HGNC Approved Gene Symbol: DEFB119
Cytogenetic location: 20q11.21 Genomic coordinates (GRCh38): 20:31,377,163-31,390,649 (from NCBI)
Beta-defensins are a family of typically cationic antimicrobial peptides that share a signature motif consisting of 6 conserved cysteines. DEFB119 and its splice variant, DEFB120, are part of a cluster of beta-defensins on chromosome 20q11.1 that are expressed in the male reproductive tract (Radhakrishnan et al., 2005).
By genomic sequence analysis using multiple computational tools, Schutte et al. (2002) identified human DEFB119 and DEFB120. Both predicted proteins contain the 6-cysteine domain characteristic of beta-defensins. EST database analysis suggested that both DEFB119 and DEFB120 are transcribed.
Using RT-PCR and EST database analysis, Radhakrishnan et al. (2005) cloned human and macaque DEFB119 and DEFB120 and determined that they are splice variants. The predicted human DEFB119 protein contains 84 amino acids, whereas the predicted DEFB120 protein contains 88 amino acids. DEFB119 and DEFB120 both contain the conserved 6-cysteine signature motif. RT-PCR of human tissues revealed abundant DEFB119 and DEFB120 expression in the male reproductive tract only. DEFB119 expression was abundant in testis and the caput region of epididymis, but low in the corpus region. In contrast, DEFB120 expression was abundant in proximal epididymis (caput and corpus) and low in distal epididymis and testis.
Radhakrishnan et al. (2005) determined that, unlike most beta-defensin genes, DEFB119 contains 3 exons instead of 2. The first exon is shared by both DEFB119 and DEFB120 variants, whereas exons 2 and 3 are alternatively spliced.
By genomic sequence analysis, Schutte et al. (2002) mapped the DEFB119 gene within a beta-defensin gene cluster on chromosome 20q11.1. The syntenic mouse cluster is located on chromosome 2.
Evolutionary analyses by Radhakrishnan et al. (2005) suggested that the beta-defensin gene cluster on chromosome 20q11.1, which includes DEFB119, originated by a series of duplication events and by positive selection.
Schutte et al. (2002) noted that mouse and human beta-defensin genes are designated using the stem roots 'Defb' and 'DEFB,' respectively. Mouse genes are numbered beginning with 1, whereas human genes are numbered beginning with 101. In cases where orthologous genes are confirmed, the lower gene number is used. For example, mouse beta-defensin-1 (Defb1) and human beta-defensin-1 (DEFB101) are confirmed orthologs and are therefore named Defb1 and DEFB1 (602056), respectively.
Radhakrishnan, Y., Hamil, K. G., Yenugu, S., Young, S. L., French, F. S., Hall, S. H. Identification, characterization, and evolution of a primate beta-defensin gene cluster. Genes Immun. 6: 203-210, 2005. [PubMed: 15772680] [Full Text: https://doi.org/10.1038/sj.gene.6364184]
Schutte, B. C., Mitros, J. P., Bartlett, J. A., Walters, J. D., Jia, H. P., Welsh, M. J., Casavant, T. L., McCray, P. B., Jr. Discovery of five conserved beta-defensin gene clusters using a computational search strategy. Proc. Nat. Acad. Sci. 99: 2129-2133, 2002. Note: Erratum: Proc. Nat. Acad. Sci. 99: 14611 only, 2002. [PubMed: 11854508] [Full Text: https://doi.org/10.1073/pnas.042692699]