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Biomedical subjects

I W Craig

Publications and source records attributed to I W Craig.

At least 91 records · Page 5Linked to original sources
PubMed1989

Gene of X-chromosomal congenital stationary night blindness is closely linked to DXS7 on Xp.

Congenital stationary night blindness is characterized disturbed or absent night vision that is always present at or shortly after birth and nonprogressive. The X-linked form of the disease (CSNBX; McKusick catalog no. 31050) differs from the autosomal types in that the former is frequently associated with myopia. X-chromosome-specific polymorphic DNA markers were used to carry out linkage analysis in three European families segregating for CSNBX. Close linkage without recombination was found between the disease locus and the anonymous locus DXS7, mapped to Xp11.3, assigning the mutation to the proximal short arm of the X chromosome. Linkage data obtained with markers flanking DXS7 provided further support for this localization of the gene locus. Thus, in addition to retinitis pigmentosa and Norrie disease, CSNBX represents the third well-known hereditary eye disease the locus of which is mapped on the proximal Xp and closely linked to DXS7.

Chromosome Mapping↗
PubMed1989

Localization of human monoamine oxidase-A gene to Xp11.23-11.4 by in situ hybridization: implications for Norrie disease.

A cDNA for the neurotransmitter-degrading enzyme monoamine oxidase-A (MAO-A) has been assigned by in situ hybridization to the human X chromosome and subregionally localized to Xp11.23-11.4. As restriction fragments detected by this probe are deleted in some patients with Norrie disease, this assignment provides confirmation of the localization of the disease.

Chromosome Banding↗
PubMed1989

Assignment of the coding sequence for carcinoembryonic antigen (CEA) and normal cross-reacting antigen (NCA) to human chromosome 19q13.

We have isolated and localized to chromosome 19 a genomic sequence for carcinoembryonic antigen (CEA). A human cosmid bank was screened with two degenerate oligonucleotide sequences corresponding to N-terminal segments of the protein. Sequence analysis of a selected cosmid has confirmed the presence of an exon representing the 107 amino acids of the first protein domain (plus part of a putative leader sequence). In situ hybridization of both the exon DNA sequence and a more extensive genomic fragment to replication banded chromosomes has indicated that CEA and strongly cross-hybridizing members of the CEA family can be assigned to 19q13. This conclusion is supported by studies with a somatic cell hybrid cell-line.

Antigens, Neoplasm↗
PubMed1988

Mapping of Xp21 translocation breakpoints in and around the DMD gene by pulsed field gel electrophoresis.

Balanced translocations with a breakpoint in the Xp21 region are likely to disrupt the giant Duchenne muscular dystrophy (DMD) locus and can be demonstrated in females suffering from the disease. Pulsed field gel electrophoresis allows the positioning of these breakpoints by detecting junction fragments on the derived chromosomes; DNA probes hybridizing to these fragments may be located as many as several hundred kilobases away from the breakpoints. By using this approach, 11 translocation breakpoints from the Xp21 region have been analyzed. The localization of three previously examined breakpoints was confirmed. Six other breakpoints, including a breakpoint flanking the DMD gene and not associated with the DMD phenotype, could be positioned relative to SfiI sites on a 3.5-Mb restriction map of the region.

Cell Line↗
PubMed1988

Localization of the human dopamine beta hydroxylase (DBH) gene to chromosome 9q34.

A human cDNA clone for dopamine beta hydroxylase (DBH) has been isolated from a phaeochromocytoma library. In situ hybridization of this probe to replication-banded chromosomes has localized the gene to chromosome 9q34. The structural gene for the enzyme is therefore close to the ABO blood group locus. This suggests that the previously described activity variation in levels of serum DBH may reflect alterations in either the structure or regulation of the DBH coding sequences. Both biochemical and genetic evidence therefore indicate independence of DBH from the pterin-dependent aromatic amino acid hydroxylases of the neurotransmitter pathways.

ABO Blood-Group System↗
PubMed1987

Genomic organization of human centromeric alpha satellite DNA: characterization of a chromosome 17 alpha satellite sequence.

We characterized a recombinant clone E7 containing a 1.6-kb Eco RI insert of human alpha satellite DNA (alpha DNA) which hybridized in situ predominantly to the centromere of chromosome 17. Three thousand copies of this sequence were detected on chromosome 17, although a lesser number of copies were also found on the centromeres of chromosomes 11, X, and the other human chromosomes, except Y. In the human genome, sequences homologous to E7 were organized principally as five major polymorphic (Pst I) forms of tandem alpha DNA repeats with molecular weights between 2.0 and 2.7 kb. We We studied the higher-order organization of these major forms using a series of 12 cosmid clones. Close linkage of the different polymorphic forms was demonstrated, with no two cosmids showing an identical linkage pattern. Six of the cosmid clones carried a considerable amount (20-25%) of nonhomologous (non-alpha) DNA, indicating that the repeat arrays are relatively frequently interrupted by other genomic DNA. In none of the cosmid inserts were the repeat arrays bound on both sides by non-alpha DNA, suggesting that short arrays are not common. However, some of the intervening non-alpha DNA sequences were relatively short, and vary in size from 6 to 24 kb. Our results suggest an irregular and complex pattern of organization of alpha DNA in the human genome.

Chromosome Mapping↗
PubMed1987

Physical mapping of genes and sequences at the end of the human X chromosome short arm.

Human-rodent somatic cell hybrids containing deleted and translocated human X chromosomes have been used to map genes and sequences in and around the pseudoautosomal region. The following order was found: (DXS69, DXS70, DXS143)-(DXS31, STS)-MIC2. This order is consistent with the known inheritance patterns of DXS31, STS and MIC2. Assuming that the translocations and deletions we have studied are not complex rearrangements, we conclude that the pseudoautosomal region consists of less than 5 X 10(6) bp of DNA.

Animals↗
PubMed1987

Localisation of Y chromosome sequences in normal and 'XX' males.

Three unique sequences derived from the Y chromosome have been mapped within the human genome. A Y specific sequence DYS20 is localised to Yq11.2. DXYS25 and DXYS27 are both X-Y homologous sequences which map to the Y short arm and to Xq21. DXYS25 maps more distally than DXYS27, on the Y short arm and on the X long arm. Y specific restriction fragments for these two sequences are shown to be present in the genome of two XX males, and an aberrant signal for DXYS25 is demonstrated at the tip of an X chromosome short arm in one XX male by in situ hybridisation. The implications of these findings for the location of the testis determining factor are discussed.

Chromosome Deletion↗
PubMed1985

Platelet monoamine oxidase: specific activity and turnover number in schizophrenics and their families.

Monoamine oxidase specific activities and molecular turnover numbers have been measured in families with at least two schizophrenic members. Neither measure of monoamine oxidase was different in schizophrenics compared with their first degree relatives. Molecular turnover number was remarkably similar in males and females and when the group was considered by age, diagnosis, drug status and family membership. Neither specific activity nor turnover number could be used in risk estimation for the development of schizophrenia in members of these families.

Adult↗
PubMed1985

Studies of heterogeneous mitochondrial populations in a mouse cell line: the effects of selection for or against mitochondrial genomes that confer chloramphenicol resistance.

A single nucleotide substitution in a highly conserved region of the mitochondrial genome of a mouse cell line confers both chloramphenicol resistance and an alteration to the recognition site for the endonuclease Eco RV. This has enabled a detailed study on the effects of selection on a mitochondrial population comprising initially both chloramphenicol-resistant and chloramphenicol-sensitive mitochondrial genomes. The mutation confers advantage to cells grown in the presence of chloramphenicol, but is apparently deleterious in its absence. Selection at the cellular level is sufficient to explain the results observed. Fixation, which results in cells having mitochondria of only a single type, is slow. It is probable, therefore, that mammalian oocyte mitochondria are derived from only a small number of progenitors. This would allow fixation of new mutations and explain the observed uniformity in mitochondrial genomes of the individual in the presence of extensive variation between different members of the population.

Animals↗
PubMed1985

Isolation and characterization of an alphoid centromeric repeat family from the human Y chromosome.

A collection of human Y-derived cosmid clones was screened with a plasmid insert containing a member of the human X chromosome alphoid repeat family, DXZ1. Two positive cosmids were isolated and the repeats they contained were investigated by Southern blotting, in situ hybridization and sequence analysis. On hybridization to human genomic DNAs, the expected cross-hybridization characteristic of all alphoid sequences was seen and, in addition, a 5500 base EcoRI fragment was found to be characteristic of a Y-specific alphoid repeat. Dosage experiments demonstrated that there are about 100 copies of this 5500 base EcoRI alphoid fragment on the Y chromosome. Studies utilizing DNA from human-mouse hybrids containing only portions of the Y chromosome and in situ hybridizations to chromosome spreads demonstrated the Y centromeric localization of the 5500 base repeat. Cross-hybridization to autosomes 13, 14 and 15 was also seen; however, these chromosomes lacked detectable copies of the 5500 base EcoRI repeat sequence arrangement. Sequence analysis of portions of the Y repeat and portions of the DXZ1 repeat demonstrated about 70% homology to each other and of each to the human consensus alphoid sequence. The 5500 base EcoRI fragment was not seen in gorilla, orangutan or chimpanzee male DNA.

Animals↗
PubMed1984

Assignment of the haemophilia B (factor IX) locus to the q26-qter region of the X chromosome.

Two independent approaches have provided an assignment for the factor IX (Haemophilia B) locus to Xq26-qter, the distal region of the X chromosome long arm. Cloned DNA sequences of the gene were hybridized to restriction enzyme digests of DNA prepared from a series of somatic cell hybrids containing different X-chromosomal regions and also in situ to prepared metaphase chromosomes.

Animals↗
PubMed1983

The isolation of an antimycin A-resistant human cell line.

An antimycin A-resistant derivative of the human cell line, D98, has been obtained by selective mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine. The derivative, designed MA65, is capable of continuous growth in 15 microM antimycin and the resistant phenotype is stable in the absence of selection. MA65 is not cross-resistant to chloramphenicol or triethyl tin. Crude membrane preparations from MA65 after propagation in medium containing antimycin have normal succinate-cytochrome c oxidoreductase activity and the respiratory activity of whole cells continues in the presence of the drug. The mitochondrially synthesized proteins of D98 and MA65 are similar when compared on sodium dodecyl sulphate (SDS), or isoelectric focusing gels, but there is a reproducible difference in the extent of labelling of one band detected by isoelectric focusing. Genetic analysis is consistent with the existence of a cytoplasmically localized determinant conferring resistance.

Antimycin A↗