Structure of genes for sperm-specific nuclear basic protein (SP4) in Xenopus laevis

• Published in: Biochimica et Biophysica Acta (BBA) - General Subjects Vol. 1245; no. 3; pp. 430 - 438
• Main Authors: Mita, Koichi, Ariyoshi, Nobuyuki, Abé, Shin-Ichi, Takamune, Kazufumi, Katagiri, Chiaki
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 14.12.1995; Elsevier BV
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Male; Molecular Sequence Data; Nuclear Proteins; Nuclear Proteins - genetics; Protamine; Sequence Alignment; Sequence Analysis; Sperm-specific nuclear basic protein; Spermatogenesis; Spermatozoa; Spermatozoa - metabolism; Xenopus; Xenopus laevis; Xenopus laevis - genetics; Xenopus laevis - metabolism; Xenopus Proteins; Xenopus; Sperm-specific nuclear basic protein; Spermatogenesis; Protamine
• DOI: 10.1016/0304-4165(95)00124-7
• ISSN: 0304-4165; 0006-3002

Nuclear basic proteins in sperm of Xenopus laevis consist of 6 sperm-specific proteins (SPs1–6) in addition to somatic core histones. Using a cDNA for SP4 as a probe, we cloned genomic DNA containing SP4 genes from a genomic library constructed from recombinant λ bacteriophage containing 12.0 kbp- EcoRI digests of J-strain X. laevis liver DNA. Construction of restriction maps based on Southern blot analysis revealed the existence of a total of five SP4 genes which are arranged in a tandemly repeated array forming a cluster of simple multigenes per haploid genome, over a range of 18 kbp. Among these genes, the one located at the most upstream position differed from others in possessing a single base substitution which gave rise to a replacement of one out of 78 amino acid residues. The DNA containing the second to the fourth SP4 genes, arranged at about 3 kbp intervals each, was totally sequenced for 10 165 bp. Each gene was found to contain one intron, typical TATA and CCAAT boxes in the 5′-flanking region, and a polyadenylation signal in the 3′-flanking region. Comparative sequence analyses revealed three regions of extensive homology within the upstream non-coding region among three genes, suggesting a possible relevance to their expression at a particular phase of spermatogenesis and/or in testis.