Structure of genes for sperm-specific nuclear basic protein (SP4) in Xenopus laevis.
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 lambda 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.
Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan.
K
K
Mita
N
N
Ariyoshi
S
S
Abé
K
K
Takamune
C
C
Katagiri
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics*; D016415:Sequence Alignment; D017421:Sequence Analysis; D013094:Spermatozoa / Q000378:metabolism*; D029867:Xenopus Proteins; D014982:Xenopus laevis / Q000235:genetics / Q000378:metabolism*
D009687:Nuclear Proteins; C095601:SP4 protein, Xenopus; D029867:Xenopus Proteins