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Biochemical Genetics (v.39, #3-4)
Effect of Ionic Concentration on the Higher-Order Structure of Prophenol Oxidase in Drosophila melanogaster by Hiroshi Sezaki; Nobuko Kawamoto; Nobuhiko Asada (pp. 83-92).
Phenol oxidase in Drosophila melanogaster occurs as precursors designated prophenol oxidases A1 and A3. Crossing experiments between isozyme variants proved that prophenol oxidase in this species is a homodimer. Prophenol oxidases were partially purified using ammonium sulfate fractionation, phenyl Sepharose, and DEAE-cellulose column chromatography. The preparations were mixed, then dialyzed against buffer containing varying salt concentrations. The resulting prophenol oxidase was analyzed by gel electrophoresis. At 20 mM KCl or NaCl, two bands of phenol oxidase were observed, corresponding to the parental ones as monomer, whereas at 200 mM KCl or NaCl, three bands appeared in the gel, one being a dimer. The monomer–dimer reversibility of the Drosophila prophenol oxidase depends on the salt concentrations. The phenol oxidase activity remained unaffected within the KCl concentrations tested. Considering the ionic concentration of Drosophila hemolymph, these results indicate that prophenol oxidase exists as a dimer in vivo, and the higher-order structure of prophenol oxidase can be altered reversibly by ionic concentrations in vitro.
Keywords: phenol oxidase; Drosophila; reversibility; structure
Note: Genetic Structure and Heterozygosity Variation Between Generations of Ophiopogon xylorrhizus (Liliaceae s.l.), an Endemic Species in Yunnan, Southwest China
by Tianhua He; Guangyuan Rao; Ruilin You; Song Ge; Daming Zhang (pp. 93-98).
Male Accessory Gland Secretory Proteins in a Few Members of the Drosophila nasuta Subgroup by K. Ravi Ram; S. R. Ramesh (pp. 99-115).
Male accessory gland secretory proteins in seven members of the Drosophila nasuta subgroup have been analyzed by SDS-PAGE. The study revealed remarkable simplicity in the patterns. The protein fractions, which migrate in three groups, could be categorized as “major” and “minor.” The number of major fractions varies from a maximum of eight to a minimum of four. Group I consists of high molecular weight fractions, and group III, low molecular weight fractions. Among different members analyzed, the variation with respect to pattern and the number of fractions are confined largely to group III protein fractions, while group I and II fractions are found to be conserved to a greater extent. These proteins are PAS positive and group III fractions are not sensitive to silver staining. Analysis of these tissue specific proteins in the F1 and F2 of interspecific crosses and backcross progeny as well as volume analysis revealed that a 26-kD fraction in D. n. nasuta follows an autosomal pattern of inheritance, while a 55-kD and a 25-kD fraction in D. n. albomicans and a 24-kD fraction in D. n. kepulauana follow an X-linked pattern of inheritance.
Keywords: Drosophila nasuta subgroup; male accessory glands; secretory proteins; SDS-PAGE; inheritance pattern
Identification of a Human LNX Protein Containing Multiple PDZ Domains by Yi Xie; Wei Zhao; Wei Wang; Sihui Zhao; Rong Tang; Kang Ying; Zongxiang Zhou; Yumin Mao (pp. 117-126).
Recently PDZ5 domains have been recognized as crucial organizers of protein complexes at the plasma membrane. Here we report the cloning of a novel 3.7-kb cDNA LNX from a human fetal brain cDNA library. The deduced amino acid sequence shares about 88% identity with the p70 form of Lnx, which is the mouse ligand of Numb protein X. Motif analysis reveals five protein-interaction modules conservative to those in the Lnx protein, including four PDZ domains and a NPXY motif for binding of the Numb PTB domain. Northern blot analysis shows that the length of the transcript in brain is distinct from those in other tissues. By radiation hybrid mapping, we localize the LNX gene to human chromosome 4q12 between marker D4S1577 and marker D4S1594. We predict that LNX may be important for the organization of signaling complexes in Numb-involved pathways or pathways regulated by other PTB-containing proteins.
Keywords: PDZ; ligand of Numb protein X; signal transduction; asymmetric cell division
Male Hybrid Sterility of Mice with the Genomic Region of the KitW Mutation and the KitS Allele from Mus spretus by Samir El-Shazly; Kwang-Won Seo; Abeer El-Nahas; Gene P. Ables; Atsushi Asano; Tomomasa Watanabe (pp. 127-137).
Two congenic strains, C57BL-KitW and C57BL-KitS, were generated. The KitW allele originated from strain WB-KitW and the KitS allele from Mus spretus. The KitW/KitS males showed hybrid sterility with small testes, but the females were fertile. The development of the seminiferous tubules of KitW/KitS males stopped before the spermatocyte stage and they were almost free of sperm. The Kit gene is located at position 42 on chromosome 5. We investigated in the C57BL-KitS congenic strain which part of the chromosomal region adjacent to the KitS allele is introduced from SPR into a C57BL background. The region between positions 42 and 44 was derived from SPR. Eleven amino acid substitutions of the KitS cDNA were detected by comparison with the sequence data of the +Kit cDNA from C57BL; seven were in the extracellular domain, one in the transmembrane domain, two in the kinase I domain, and one in the carboxy-terminal tail. The Kit mRNA derived from both KitW and KitS alleles was expressed in the sterile testes of KitW/KitS males.
Keywords: male hybrid sterility; Kit gene; KitW allele; wild mice
Note: Loss of Expression of Alcohol Dehydrogenase in Adult Males of Drosophila pachea
by Edward Pfeiler; Therese A. Markow (pp. 139-144).