The sequence of a porcine cDNA encoding α-lactalbumin

A cDNA clone encoding porcine α-lactalbumin (αLA) was isolated and sequenced. The longest clone was 688 nucleotides (nt) long and encoded a preprotein of 141 amino acids (aa) including a leader peptide of 19 aa. The porcine cDNA exhibited a nt similarity of between 72.2%–83.5% to other αLA cDNAs and an aa similarity of between 50.8%–85.2% with other αLA aa sequences. The derived aa sequence varied at three positions from a previously reported sequence for porcine αLA obtained by direct aa sequencing.     

Cloning and analysing of 5‘ flanking region of Xenopus organizer gene noggin

Xenopus organizer specific gene noggin possesses nearly all the characterestic properties of the action of organizer to specify the embryonic body acis.To analyze how the maternal inherited factors control its expression pattern,we cloned the 5‘ regulatory region of noggin gene.The 1.5 kb upstream sequense could direct reporter gene to express in vivo and data from deletion analysis indicated that a 229 base pair fragmet is essential for activating noggin expression.We further demonstrated that the response elements within this regulatory region were indeed under the control of growth factor activin and Wnt signaling pathway components.     

Formaldehyde kills spores of Bacillus subtilis by DNA damage and small, acid-soluble spore proteins of the ααααααα/βββββββ-type protect spores against this DNA damage

Killing of wild-type spores of Bacillus subtilis with formaldehyde also caused significant mutagenesis; spores (termed α⁻β⁻) lacking the two major α/β-type small, acid-soluble spore proteins (SASP) were more sensitive to both formaldehyde killing and mutagenesis. A recA mutation sensitized both wild-type and α⁻β⁻ spores to formaldehyde treatment, which caused significant expression of a recA - lacZ fusion when the treated spores germinated. Formaldehyde also caused protein–DNA cross-linking in both wild-type and α⁻β⁻ spores. These results indicate that: (i) formaldehyde kills B. subtilis spores at least in part by DNA damage and (b) α/β-type SASP protect against spore killing by formaldehyde, presumably by protecting spore DNA.     

Complete nucleotide sequence of the chicken alpha A-crystallin gene and its 5' flanking region

The chicken alpha A-crystallin gene and 2.6 kb of its 5' flanking sequence have been isolated and characterized by electron microscopy and sequencing. The structural gene is 4.5 kb long and contains two introns, each approx. 1 kb in length. The first intron divides codons 63 and 64, and the second intron divides codons 104 and 105, as in rodents. There is little indication that the insert exon of rodents (an alternatively spliced sequence) is present in complete form in the chicken alpha A-crystallin gene; small stretches of similarity to this sequence were found throughout the gene. The 5' flanking sequence of the chicken alpha A-crystallin gene shows considerable sequence similarity with other mammalian alpha B-crystallin genes. In addition, one consensus sequence (GCAGCATGCCCTCCTAG) present in the 5' flanking region of the chicken alpha A-crystallin gene was found in the 5' flanking region of most reported crystallin genes.     

Characterization of sequence polymorphisms from microsatellite flanking regions in <Emphasis Type="Italic">Vitis</Emphasis> spp

Single nucleotide polymorphisms or SNPs are the most abundant form of genetic variation in the genome of plants and animals. Microsatellites are hypervariable regions of genome, while their flanking regions are assumed to be as conserved as the average of the genome. In the present study, flanking sequences of 10 microsatellite loci were compared in different cultivars of Vitis to determine the existing polymorphism. For every microsatellite, about 8 homozygous cultivars (regarding the microsatellite genotype) were chosen for sequencing. A total of 45 different varieties of Vitis and 91 sequences were analysed. Sequence polymorphisms were detected for all the microsatellite flanking regions studied, including single nucleotide polymorphisms (SNPs), insertions and deletions. The number of identified changes varied considerably among the loci with a frequency of one polymorphism every 41 nucleotides, being VVMD5 the most polymorphic one. A number of SNPs were used to design SNP markers, which were scored by dideoxy single base primer extension and capillary electrophoresis methodology. These SNP markers were employed to genotype 21 cultivars of Vitis vinifera and 4 varieties of other Vitis species. The utility of the markers developed as well as their utility for varietal identification and pedigree studies is discussed, using a similar study carried out with the 10 microsatellites as a reference.     

The DNA sequence of the 5' flanking region of the human beta-globin gene: evolutionary conservation and polymorphic differences.

We have determined the DNA sequence of a 1464 bp segment immediately flanking the 5' side of the human beta-globin gene. The sequence shows little similarity to the corresponding regions of the epsilon- or gamma-globin genes. There is about 75% homology, however, between the 5' extragenic regions of the beta-globin genes of man, goat and rabbit respectively. The mouse beta minor globin gene, but not the mouse beta major globin gene, also shares this extensive homology. A short segment of simple sequence DNA is found from about 1418 to 1388 bp upstream from the human beta-globin gene which consists of repeats of the sequence (TTTTA). Similar DNA sequences are also found at several sites in the large intron of the beta-globin gene. We have compared the DNA sequence of the 5' extragenic region of the normal beta-globin gene with the same segment of the beta-globin gene of a patient with beta thalassaemia. Of the two nucleotide differences observed, one generates a polymorphic HinfI site present 990 bp upstream from the beta-globin gene in the thalassaemic beta-globin and absent in the normal gene. A second beta thalassemic beta-globin gene which has the same molecular defect as the above mentioned case, however, lacks this HinfI site. It is therefore not yet clear whether this HinfI site will have any value in prenatal diagnosis of beta thalassaemia.     

Application of Mitochondrial DNA Polymorphism to Meloidogyne Molecular Population Biology

Recent advances in molecular biology have enabled the genotyping of individual nematodes, facilitating the analysis of genetic variability within and among plant-pathogenic nematode isolates. This review first describes representative examples of how RFLP, RAPD, AFLP, and DNA sequence analysis have been employed to describe populations of several phytonematodes, including the pinewood, burrowing, root-knot, and cyst nematodes. The second portion of this paper evaluates the utility of a size-variable mitochondrial DNA locus to examine the genetic structure of Meloidogyne isolates using two alternate methodologies, variable number tandem repeat (VNTR) and repeat associated poiymorphism (RAP) analysis. VNTR analysis has revealed genetic variation among individual nematodes, whereas RAP may provide useful markers for species and population differentiation.     

Genetic variation in skipjack tuna Katsuwonus pelamis(L.) using PCR‐RFLP analysis of the mitochondrial DNA D‐loop region

A high level of genetic diversity was observed in Katsuwonus pelamis populations from India ( h  = 0·952, ne  = 14·3) and Japan ( h  = 0·897, ne  = 8·9). The log‐likelihood ( G )‐based exact test revealed significant heterogeneity in the distribution of haplotypes between the two populations ( P  < 0·01, s . e . = 0·001). This result suggests that the two populations should now be treated as demographically independent and managed separately.     

Restriction fragment length polymorphisms for growth hormone, prolactin, osteonectin, α crystallin, γ crystallin, fibronectin and 21-steroid hydroxylase in cattle

Summary. Genomic DNAs from animals representing six breeds of cattle (Angus, Brahman, Hereford, Holstein, Jersey and Texas Longhorn) were screened with cloned gene probes in a search for restriction fragment length polymorphisms (RFLPs). Eleven RFLPs were identified using seven different probes: growth hormone, prolactin, osteonectin, α A-crystallin, γ crystallin, fibronectin and 21-steroid hydroxylase. The frequencies of the alleles identified by each probe were calculated and compared in a limited sampling of the six bovine breeds. These polymorphisms greatly enhance the pool of immunogenetic, biochemical and molecular markers available in cattle for linkage analysis, testing of parentage, and distinction of breeds.     

Analysis of genetic variation in the Belgian Blue Cattle breed using DNA sequence polymorphism at the growth hormone, low density lipoprotein receptor, α-subunit of glycoprotein hormones and thyroglobulin loci

Summary. New DNA sequence polymorphisms were identified at four bovine autosomal loci: growth hormone, low density lipoprotein receptor, α-subunit of glycoprotein hormones and thyroglobulin. Assuming independent assortment between these polymorphisms, the probabilities to be heterozygous at these four loci are 0.48, 0.36, 0.10 and 0.77 respectively, within the Belgian Blue Cattle breed (BBCB). Nucleotide diversity was estimated, showing that animals from the BBCB are heterozygous for 1/1450 nucleotides, a value significantly lower than the 1/500 value found in man. Moreover, we have estimated that the mutation rate at the cytosines of CG dinucleotides is about 10 times higher than that for other nucleotides.     

Analysis of the nucleotide sequence of the Mycoplasma hominis tuf gene and its flanking region

A gene from Mycoplasma hominis PG21 similar to the tuf gene encoding the elongation factor Tu (EF-Tu) of Escherichia coli was cloned and sequenced. The 1193-bp open reading frame flanked by a putative promoter and a potential stem-and-loop structure encoded a 44-kDa polypeptide. The tuf gene of M. hominis PG21 has the lowest G + C content seen in prokaryotes (38.2%). A gene (mhlmp1) encoding a variable surface exposed membrane protein (LMP1) was found downstream the 3' end of the tuf gene. It was found that the highly conserved tuf gene was linked to the highly variable mhlmp1 gene in 26 different M. hominis strains.     

鹅卵清蛋白基因5'端调控区的克隆和序列分析

通过PCR技术从产蛋鹅输卵管基因组中扩增出1．2kb的鹅清蛋白基因5’端调控区,将其亚克隆入phD18-T载体的多克隆位点(标记为pOV),经酶切和测序鉴定：扩增产物只有3个碱基发生了突变,其TATA框、组织特异性因子和卵清蛋白上游启动子均未发生变异,表明鹅清蛋白基因5’端调控区可作为启动外源基因表达的调控序列。为构建其启动外源基因的质粒表达载体奠定了研究基础。