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C D Boyd

Publications and source records attributed to C D Boyd.

At least 91 records · Page 5Linked to original sources
PubMed1986

The single copy gene coding for human alpha 1 (IV) procollagen is located at the terminal end of the long arm of chromosome 13.

Using dual-laser sorted chromosomes and spot-blot analysis, we have previously assigned genomic DNA sequences coding for human alpha 1 (IV) procollagen to chromosome 13 (Pihlajaniemi et al. 1985). By in situ hybridization to normal chromosomes and chromosomes with 13q deletions, we now report the localization of this gene to the terminal end of the long arm of chromosome 13. In addition, Southern and slot blot hybridization analysis clearly show that these genomic sequences are present only once per haploid genome.

Base Sequence↗
PubMed1986

Large introns in the 3' end of the gene for the pro alpha 1 (IV) chain of human basement membrane collagen.

Using a recently characterized cDNA clone (HT-21) coding for the pro alpha 1 (IV) chain of human type IV procollagen, we have isolated three clones from a bacterio-phage lambda Charon 4A library of human genomic DNA. The intron/exon structure of the pro alpha 1 (IV) genomic clones was analyzed by heteroduplex electron microscopy and nucleotide sequencing. The analysis showed that the introns separating exons 2-9 are large and have a total length of over 12,000 base pairs (bp). Six of seven exons at the 3' end of the gene coded for -Gly-Xaa-Yaa-repeats of the collagenous part of the chain. Five of the -Gly-Xaa-Yaa- coding exons (numbers 5-9) varied in size between 72 bp and 134 bp, and none of them were 54 bp or multiples thereof. A sixth exon (exon 4) was a junction exon containing 71 bp coding for -Gly-Xaa-Yaa- sequences and 142 bp coding for the carboxyl-terminal noncollagenous domain (NC-1). The seventh exon (exon 3, 178 bp) coded for sequences of the NC-1 domain. Five of the six -Gly-Xaa-Yaa- coding exons began with the second base coding for glycine, and only one exon began with a complete glycine codon at the 5' end. The results (i) suggest that the gene for the pro alpha 1(IV) chain of human basement membrane collagen is significantly larger than the genes for fibrillar collagens and (ii) show that it lacks the 54-bp exon repeats characteristic of fibrillar collagen genes.

Base Sequence↗
PubMed1985

cDNA clones coding for the pro-alpha1(IV) chain of human type IV procollagen reveal an unusual homology of amino acid sequences in two halves of the carboxyl-terminal domain.

We report the isolation and characterization of cDNA clones coding for part of the pro-alpha1(IV) chain of human type IV procollagen. A cDNA library was prepared from total RNA isolated from a cultured human tumor cell line, HT-1080, and screened with a cloned mouse cDNA coding for the pro-alpha1(IV) chain. The largest cDNA clone encoded for 185 amino acid residues of the -Gly-X-Y-sequence of the human pro-alpha1(IV) chain, all of the globular carboxyl-terminal domain, and the 3' noncoding region. The results provide the first complete sequence for the carboxyl-terminal globular portion of a type IV procollagen chain. A striking feature of the carboxyl-terminal globular domain was a homology between the first and second half of the structure. The homology involved all 12 cysteine residues, the spacing between the cysteine residues, and many adjacent amino acids. The results raised the possibility that evolution of the globular domain involved duplication of an ancestral sequence coding for about 100 amino acids, 6 of which were cysteine. The homology, however, was more apparent in the amino acid sequence than in the nucleotide sequence, and, therefore, the results suggested that the homology reflects selective pressure on the function of the protein more than conservation of the nucleotide sequences in the gene. The nucleotide sequences of the 3' noncoding region of the cDNAs contained four polyadenylation signals of AATAAA. Three or four of the polyadenylation signals were probably used in transcription, since one major and two minor smaller RNA species from human skin fibroblasts hydridized with the cDNAs. In further studies, sorted human chromosomes were used to locate the gene for the pro-alpha1(IV) chain on chromosome 13.

Amino Acid Sequence↗
PubMed1985

Afrikander cattle congenital goiter: size heterogeneity in thyroglobulin mRNA.

The mRNA coding for thyroglobulin in cattle homozygous for an autosomal recessive defect of thyroglobulin synthesis was investigated using a recombinant plasmid containing bovine mRNA coding sequence. Total RNA preparations from goiter contained one third of the thyroglobulin mRNA sequences found in normal thyroid tissue. This mRNA was not translated into thyroglobulin by Xenopus oocytes. Northern transfer analysis revealed both a normal sized and a smaller thyroglobulin mRNA in the goiter.

Animals↗
PubMed1985

Defective splicing of thyroglobulin gene transcripts in the congenital goitre of the Afrikander cattle.

The structure of thyroglobulin mRNA was analyzed in an inbred herd of Afrikander cattle with hereditary goitre. Northern transfer of RNA from affected animals revealed both a shorter (approximately 7100 bases) and a normal-sized (approximately 8200 bases) thyroglobulin mRNA when hybridized to bovine thyroglobulin cDNA clones. S1 nuclease mapping experiments established that 1100 bases are deleted in the 5' region of the smaller mRNA. Electron microscopy of RNA from animals with goitre hybridized to a bovine genomic DNA clone showed that the region deleted corresponds to exon 9 of the thyroglobulin gene. Southern blot analysis of the exon 9 region revealed differences between affected and control animals with the enzymes PstI and TaqI. Although they could reflect a linkage disequilibrium between the mutation and restriction fragment length polymorphism, it is noteworthy that these differences map in the region of the exon 9/intron 9 junction. Our results show that a genetic lesion in the thyroglobulin gene causes aberrant splicing of the pre-mRNA, and suggest that the responsible mutation is at the exon 9/intron 9 junction.

Animals↗
PubMed1985

Two new polymorphic markers in the human pro alpha 2(1) collagen gene.

Structural defects in the human type 1 collagen genes are known to be the cause of several inherited disorders of connective tissue, such as osteogenesis imperfecta. The analysis and prenatal diagnosis of these disorders would be facilitated by establishing a set of polymorphic markers at these gene loci. We have previously reported the presence of an Msp 1 restriction fragment length polymorphism in the pro alpha 2 (1) collagen genes of several Southern African populations (Grobler-Rabie et al., in press). This report describes the detection of a Bgl II and an EcoRI polymorphism in the pro alpha 2 gene of South African Blacks.

Black People↗
PubMed1985

Characterization of the messenger RNA population coding for components of viperid snake venom.

Total polyadenylated messenger RNA was prepared from the milked venom glands of the South African puff adder (Bitis arietans) and translated in an in vitro translation system. The products of cell free synthesis were immunoprecipitable with puff adder venom antiserum. Treatment of these cell free products with a dog pancreas microsomal membrane preparation demonstrated the presence of signal peptides. Northern blot hybridization of total puff adder venom gland mRNA to its complementary single stranded copy DNA revealed two discrete mRNA populations coding for the major components of puff adder venom. The relative amounts of these polyadenylated mRNA sequences changed during the onset of venom synthesis, suggesting mRNA deadenylation, general endonucleolytic RNA degradation and selective degradation of high molecular weight message components.

Animals↗
PubMed1985

Polymorphism of DNA sequence in the human pro alpha 2(I) collagen gene.

The human pro alpha 2(I) collagen gene was analysed for the presence of restriction fragment length polymorphisms. DNA from randomly selected unrelated persons of three Southern African populations was cleaved with one of eight different restriction enzymes, electrophoresed, blotted, and hybridised with cDNA and genomic probes specific for the pro alpha 2(I) gene. An MspI polymorphism was detected which results from the loss of a cleavage site within the 3' half of the gene. In two of the populations studied, the polymorphism occurred at significant frequencies, and should therefore prove useful as a genetic marker for the study of inherited disorders of connective tissue involving collagen structure or biosynthesis.

Chromosome Mapping↗
PubMed1984

South African human genes in health and disease--a molecular genetics approach.

Recombinant DNA technology is playing an increasingly important role in diagnostic confirmation, carrier detection and the prenatal diagnosis of inherited disorders. This article summarizes current progress in the application of this technology to clinically important genetic conditions in South Africa and outlines its potential role in the future practice of medical genetics in this country.

Anemia, Sickle Cell↗
PubMed1984

Evidence for transcriptional regulation of the myosin heavy chain gene during myogenesis.

One of the changes accompanying skeletal muscle cell (myoblast) fusion is a dramatic increase in synthesis of muscle specific proteins, one of which is myosin. The underlying mechanism for this burst in synthesis is not yet understood but may occur by two mechanisms: (a) gradual storage of mRNA and translational control as found by others or (b) gene activation and rapid synthesis of mRNA for immediate translation. In this paper we show that the myosin gene changes its organization such that postfusion skeletal muscle cells show an increased susceptibility to DNase I, a recognized probe for gene activation. We also show that this change accompanies an increase in rate of transcription and an increased cell content of myosin heavy chain mRNA. This work shows that transcriptional control is an important mechanism during muscle cell development in addition to the translational control shown by other workers.

Animals↗
PubMed1980

Structural organization of a 17 KB segment of the alpha 2 collagen gene: evaluation by R loop mapping.

A recombinant phage, SpC3, containing a 17 kb genomic DNA insert representing approximately 60% of the 3' portion of the sheep collagen alpha 2 gene, was evaluated by electron microscopic R loop analysis. A minimum of 17 intervening sequences (introns) and 18 alpha 2 coding sequences (exons) were mapped. With the exception of the 850 base pair exon located at the extreme 3' end of the insert, all exons contained 250 base pairs or less. The total length of all the exons in SpC3 was 3,014 base pairs. The length distribution of the 17 introns ranged from 300 to 1600 base pairs; together, all of the introns comprised 14,070 base pairs of SpC3 DNA. Thus, the DNA region required for coding the interspersed 3 kb of alpha 2 collagen genetic information was 5.6 fold longer than the corresponding alpha 2 mRNA coding sequences.

Animals↗
PubMed1980

Isolation and characterization of a 15-kilobase genomic sequence coding for part of the Pro alpha 2 chain of sheep type I collagen.

DNA fragments, prepared by partial Eco RI digestion of fetal sheep liver genomic DNA, were used to prepare a "library" of amplified genomic sequences with the lambda vector Charon 4A. Several recombinant plaques were identified by their ability to hybridize to 32P-labeled cDNA prepared from fetal sheep tendon type I procollagen mRNA. Two of these recombinant DNA bacteriophages (SpC3 and SpC7) were identified as containing procollagen pro alpha 2 gene sequences by their ability to specifically anneal to procollagen pro alpha 2 mRNA. Restriction endonuclease and hybridization to a cloned pro alpha 2 cDNA demonstrated that approximately half (2.5 kilobases) of the pro alpha 2 mRNA sequence is distributed over 15 kilobases of genomic DNA. Restriction maps of SpC3 and SpC7 demonstrated that these two DNA fragments contain overlapping sequences of the pro alpha 2 gene. Electron microscopy and R-loop analysis of SpC3 revealed that at least 12 to 16 intervening sequences are distributed throughout the length of this gene fragment.

Animals↗
PubMed1977

Direct evidence that ribosome bound RNA-dependent RNA polymerase does not play a role in globin messenger RNA replication.

The radioactively labelled product of RNA-dependent RNA polymerase+ from ribosomes of immature chicken erythrocytes was tested for the presence of newly replicated globin mRNA using unlabelled globin complementary DNA. No radioactively labelled globin mRNA sequences were found in the product, providing direct confirmation that this RNA-dependent RNA polymerase is not involved in globin mRNA amplification.

Animals↗