Characterization of the mouse Dazap1 gene encoding an RNA-binding protein that interacts with infertility factors DAZ and DAZL

BACKGROUND: DAZAP1 (DAZ Associated Protein 1) was originally identified by a yeast two-hybrid system through its interaction with a putative male infertility factor, DAZ (Deleted in Azoospermia). In vitro, DAZAP1 interacts with both the Y chromosome-encoded DAZ and an autosome-encoded DAZ-like protein, DAZL. DAZAP1 contains two RNA-binding domains (RBDs) and a proline-rich C-terminal portion, and is expressed most abundantly in the testis. To understand the biological function of DAZAP1 and the significance of its interaction with DAZ and DAZL, we isolated and characterized the mouse Dazap1 gene, and studied its expression and the subcellular localization of its protein product. RESULTS: The human and mouse genes have similar genomic structures and map to syntenic chromosomal regions. The mouse and human DAZAP1 proteins share 98% identity and their sequences are highly similar to the Xenopus orthologue Prrp, especially in the RBDs. Dazap1 is expressed throughout testis development. Western blot detects a single 45 kD DAZAP1 protein that is most abundant in the testis. Although a majority of DAZAP1 is present in the cytoplasmic fraction, they are not associated with polyribosomes. CONCLUSIONS: DAZAP1 is evolutionarily highly conserved. Its predominant expression in testes suggests a role in spermatogenesis. Its subcellular localization indicates that it is not directly involved in mRNA translation

Phylogenetic and Molecular Characterization of a 23S Ribosomal-Rna Gene Positions the Genus Campylobacter in the Epsilon-Subdivision of the Proteobacteria and Shows That the Presence of Transcribed Spacers Is Common in Campylobacter Spp

The nucleotide sequence of a 23S rRNA gene of Campylobacter coli VC167 was determined. The primary sequence of the C. coli 23S rRNA was deduced, and a secondary-structure model was constructed. Comparison with Escherichia coli 23S rRNA showed a major difference in the C. coli rRNA at approximately position 1170 (E. coli numbering) in the form of an extra sequence block approximately 147 bp long. PCR analysis of 31 other strains of C. coli and C. jejuni showed that 69% carried a transcribed spacer of either ca, 147 or ca. 37 bp. Comparison of all sequenced Campylobacter transcribed spacers showed that the Campylobacter inserts were related in sequence and percent G+C content. All Campylobacter strains carrying transcribed spacers in their 23S rRNA genes produced fragmented 23S rRNAs. Other strains which produced unfragmented 23S rRNAs did not appear to carry transcribed spacers at this position in their 23S rRNA genes. At the 1850 region (E. coli numbering), Campylobacter 23S rRNA displayed a base pairing signature most like that of the beta and gamma subdivisions of the class Proteobacteria, but in the 270 region, Campylobacter 23S rRNA displayed a helix signature which distinguished it from the alpha, beta, and gamma subdivisions. Phylogenetic analysis comparing C. coli VC167 23S rRNA and a C. jejuni TGH9011 (ATCC 43431) 23S rRNA with 53 other completely sequenced (eu)bacterial 23S rRNAs showed that the two campylobacters form a sister group to the alpha, beta, and gamma proteobacterial 23S rRNAs, a positioning consistent with the idea that the genus Campylobacter belongs to the epsilon subdivision of the class Proteobacteria

Prevention of Ocular Scarring Post Glaucoma Filtration Surgery Using the Inflammatory Cell and Platelet Binding Modulator Saratin in a Rabbit Model

Clinical Relevance: Late complications can occur with use of current antimetabolites to prevent scarring following glaucoma filtration surgery (GFS). Safer, more targeted, anti-fibrosis agents are sought. Objectives: The protein saratin has been shown to exhibit anti-fibrotic and anti-thrombotic properties in response to injury, but had not been used for glaucoma surgery. The goal of this study was to compare the efficacy of saratin with that of the widely accepted mitomycin-C (MMC) in prolonging bleb survival following GFS in the rabbit model. Two saratin delivery routes were compared; a single intraoperative topical application versus a combination of intraoperative topical application with two additional postoperative injections. Methods: Twenty-four New Zealand White rabbits underwent GFS and received either intraoperative topical saratin, intraoperative topical saratin plus two injections on post-operative days 4 and 8, balanced saline solution (BSS), or MMC. The bleb tissues and their elevation durations were compared based on clinical and histological findings. Results: Rabbits receiving topical+injections of saratin had a mean bleb survival of 33.668.5 days, significantly higher than the negative BSS controls, which averaged 17.466.0 days (p = 0.018). No improvement over BSS was seen for rabbits receiving topical saratin only (15.564.8 days, p = 0.749). Rabbits receiving saratin did not develop bleb avascularity and thinning associated with MMC treatment and there were no apparent clinical signs of toxicity

Selection on Silent Sites in the Rodent H3 Histone Gene Family

Selection promoting differential use of synonymous codons has been shown for several unicellular organisms and for Drosophila, but not for mammals. Selection coefficients operating on synonymous codons are likely to be extremely small, so that a very large effective population size is required for selection to overcome the effects of drift. In mammals, codon-usage bias is believed to be determined exclusively by mutation pressure, with differences between genes due to large-scale variation in base composition around the genome. The replication-dependent histone genes are expressed at extremely high levels during periods of DNA synthesis, and thus are among the most likely mammalian genes to be affected by selection on synonymous codon usage. We suggest that the extremely biased pattern of codon usage in the H3 genes is determined in part by selection. Silent site G + C content is much higher than expected based on flanking sequence G + C content, compared to other rodent genes with similar silent site base composition but lower levels of expression. Dinucleotide-mediated mutation bias does affect codon usage, but the affect is limited to the choice between G and C in some fourfold degenerate codons. Gene conversion between the two clusters of histone genes has not been an important force in the evolution of the H3 genes, but gene conversion appears to have had some effect within the cluster on chromosome 13