Sperm Protein Associated With The Nucleus, X-Linked Family, Member N5 (SPANXN5)

Formation of mature spermatozoa requires the temporally regulated transcription and translation of multiple testis-specific genes. By screening a human testis cDNA expression library with mononclonal antibodies that inhibit sperm function, Westbrook et al. (2000) cloned and characterized a novel gene, SPANXA1, which they named SPANX. The SPANXA1 gene encodes a deduced 97-amino acid protein with a molecular mass of approximately 11 kD. The protein contains 2 overlapping consensus single basic-type nuclear localization signals and 1 consensus bipartite basic-type nuclear localization signal. By searching for SPANX-like genes, Kouprina et al. (2004) identified several SPANXN genes, including SPANXN5. Within the SPANXN5 peptide sequence, Westbrook et al. (2006) identified a nuclear localization signal and regions rich in glutamic acid and serine.