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Biochemical Genetics (v.41, #7-8)

Characterization of Four Novel Variants of Goat β^A-Globin Gene by Monica Pirastru; Laura Manca; Bruno Masala (pp. 209-217).

Four novel alleles of the adult β-globin gene of Capra hircus were observed in an extended study on hemoglobin polymorphism in goat breeds living in the island of Sardinia. Nucleotide sequencing showed that one of these alleles is due to a 2 bp substitution at codon 125 ( $$underline {CT} o underline {GA} G,$$ G, "Leu→Glu). Two substitutions, the silent CT $$underline T o CTunderline C $$ for Leu at codon 78 and the conservative A $$underline A G o Aunderline G $$ G (Lys →Arg) at codon 104, are shared by the other three alleles, two of them having additional mutations, which suggests a common origin. The allele we provisionally called the β Y shares four out of five amino acid substitutions, together with the same polymorphisms in the IVSII, we observed previously in the rather common β E gene. This evidence allowed the origin of the β E gene to be better characterized. The data increase to seven the number of alleles at the goat β A-globin locus characterized thus far at the molecular level. A simplified nomenclature for the increasing number of goat β-globin alleles is presented.

Keywords: Hb polymorphism; β^A-globin gene; alleles; Capra hircus

Temporal and Spatial Allozyme Variation in the South American Cactophilic Drosophila antonietae (Diptera; Drosophilidae) by R. P. Mateus; F. M. Sene (pp. 219-233).

Drosophila antonietae is an endemic South American cactophilic species that uses Cereus hildmaniannus rotting cladodes as breeding sites. We assessed temporal and spatial intrapopulational allozyme variation of two natural populations. Our results suggest that environmental variation (rain precipitation) is probably influencing allozyme temporal variation. Moreover, it seems that D. antonietae does not have intrapopulation structure and has N _ev (variance effective size) ≅ 83 and N _ec (number of adult flies that colonize each rotting cladode) = 21. The deficiency of heterozygotes found must be due to null alleles, a temporal Wahlund effect, or selection against heterozygotes. Assortative mating and inbreeding are discarded. This is the first report on allozyme variation in D. antonietae. It gives some insight on intrapopulational genetics through space and time for this species. This is important to understand its general genetic variability and will be essential to future works on the natural history and evolution of this species.

Keywords: cactophilic Drosophila ; temporal variation; spatial variation; genetic variability; allozymes

A High Mobility Group Protein from the Dipteran Insects Ceratitis capitata and Bactrocera oleae by Vassiliki Aleporou-Marinou; Christina Deli; Yiannis Ninios; Barbara Agelopoulou; Haroula Marinou; Theocharis Patargias (pp. 235-243).

Nuclei from Bactrocera oleae and Ceratitis capitata larvae contain a major protein that shares most of the characteristics of vertebrate high mobility group (HMG) proteins. Proteins are extracted from nuclei with 0.35 M NaCl, are soluble in 5% perchloric acid, are relatively small (molecular weight in the range of 10–16 kDa), and have both a high basic and a high acidic amino acid content. The amino acid constitution of these proteins is similar to that of the HMGB protein family of vertebrates. The proteins cross-react with antibodies raised against the HMGD chromosomal protein of Drosophila melanogaster. The possible relatedness of these proteins to high mobility group proteins is discussed.

Keywords: HMG proteins; high mobility group-like proteins; polyacrylamide electrophoresis; western immunoblotting

Cloning and Identification of a Novel cDNA Which Encodes a Putative Protein with a DnaJ Domain and a Thioredoxin Active Motif, Human Macrothioredoxin by Shao-Hua Gu; Jin-Zhong Chen; Kang Ying; Shu Wang; Wei Jin; Ji Qian; En-Peng Zhao; Yi Xie; Yu-Min Mao (pp. 245-253).

A 3345 bp cDNA was isolated from the fetal brain cDNA library by high throughput cDNA sequencing. The cDNA with an open reading fragment (ORF) of 2241 bp encodes a 747 amino acids putative protein with a DnaJ N-terminus domain and four thioredoxin active sets. So it is named human macrothioredoxin (hMTHr). The nucleotide sequences reported in this paper have been deposited in the Genbank database under accession number AF490904 and AY089971. We used Northern blot to detect a band with a length of about 5 kb, which was ubiquitously expressed in human adult tissues with different intensities. The expression pattern was verified by RT-PCR, revealing that the transcripts were ubiquitously expressed in fetal tissues and human tumor tissues also. The transcripts in fetal tissues were more numerous than in adult tissues. The transcripts were high in adult testis, adult pancreas, fetal thymus, and fetal kidney. We have found three splice isoforms with lengths of 3483, 3345, and 2982 bp in the sequencing analysis of the RT-PCR products. They encode three putative proteins with 793, 747, and 275 amino acids, respectively. The first two putative proteins contain a DnaJ domain and four thioredoxin domains. The third putative protein only contains an N-terminus DnaJ domain and one thioredoxin active set. Blast analysis against the NCBI database revealed that the gene spans a genome sequence of about 75 kb that contains at least 25 exons and is located in human chromosome 2q32.1. The organization of the functional motifs of hMTHr suggests that the protein might be a member of a molecular chaperone family.

Keywords: human macrothioredoxin (hMTHr) ; thioredoxin; DnaJ; chaperone; splice isoform

Expression of Two Isoform mRNAs of Nucleolar Protein B23 During Rat Liver Regeneration by Yuki Nishimura; Masahiro Nishio; Yukio Furuichi; Hayato Umekawa (pp. 255-262).

Nucleolar protein B23 exists in two isoforms designated as B23.1 and B23.2, differing only in their carboxy-terminal short sequences. To clarify the levels of protein B23 isoform mRNAs in the cell cycle, we have investigated the expressions of the two mRNAs during rat liver regeneration. Both of B23 isoforms transcripts increased after a partial hepatectomy. Peaks of the mRNAs were observed after 9 h (fivefold) with B23.1 and 12 h (twofold) with B23.2, respectively. These two peaks were slightly preceding the onset of DNA synthesis, which was revealed by the activity of DNA polymerase α. From these observations, important roles of both protein B23 isoforms in stimulation of DNA polymerase α activity during rat liver regeneration were suggested.

Keywords: protein B23; protein isoforms; liver regeneration; DNA polymerase α

Note: Isoform-Dependent Phenol Oxidase Activity During the Developmental Stages in Drosophila melanogaster by Nobuhiko Asada (pp. 263-268).

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Biochemical Genetics (v.41, #7-8)

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Biochemical Genetics (v.41, #7-8)