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E Munro

Publications and source records attributed to E Munro.

8 recordsLinked to original sources
PubMed1991

The construction of human somatic cell hybrids containing portions of the mouse X chromosome and their use to generate DNA probes via interspersed repetitive sequence polymerase chain reaction.

Interspersed repetitive sequence polymerase chain reaction (IRS-PCR) has become a powerful tool for the rapid generation of DNA probes from human chromosomes present in rodent somatic cell hybrids. We have constructed a somatic cell hybrid containing a major portion of the mouse X chromosome in a human background (clone 8.0). IRS-PCR was developed for the specific amplification of mouse DNA using either of two primers from the rodent-specific portion of the murine B1 repeat. Amplification was subsequently performed with clone 8.0 and a subclone, 8.1/1, which retains a small murine X-chromosomal fragment including Hprt and the Gdx locus. A total of 15-20 discrete PCR products ranging in size from less than 500 to greater than 3000 bp were obtained from clone 8.0 with each primer. In clone 8.1/1, a subset of these bands plus some additional bands were observed. Nine bands amplified from clone 8.1/1 have been excised from gels and used as probes on Southern blots. All of the fragments behaved as single-copy probes and detected domesticus/spretus variation. They have been regionally mapped using an interspecific backcross. The probe locations are compatible with those of markers known to be present in clone 8.1/1. These results demonstrate the feasibility of this method as applied to the mouse genome and the high likelihood of generating useful DNA probes from a targeted region.

Animals↗
PubMed1989

Regional localization of human ecto-5' nucleotidase to chromosome 6q14-q21.

Human and mouse hybrids that contain fragments of human chromosome 6 as translocations were analysed for expression of ecto-5' nucleotidase enzymic activity measured by the conversion of AMP to adenosine and for antigenicity recognized by a monoclonal antibody specific for the human isozyme. Both methods allow a regional assignment of ecto-5'nucleotidase to 6q14-q21.

5'-Nucleotidase↗
PubMed1988

Mapping of 12 translocation breakpoints in the Xp21 region with respect to the locus for Duchenne muscular dystrophy.

Over 20 females have been reported to carry reciprocal X; autosome translocations with breakpoints in Xp21 and to suffer from Duchenne muscular dystrophy (DMD). We have positioned nine of these breakpoints with respect to the Duchenne gene by mapping probes from the DMD region against a panel of somatic cell hybrids, each containing one of the translocation chromosomes from a different female patient; further information has also been obtained by in situ hybridization, including the breakpoint location in a tenth DMD patient. We have also characterized two translocation breakpoints that lie in the same chromosomal region but which are not associated with the expression of DMD. All the DMD-associated translocation breakpoints examined lie at several sites within the DMD locus and between the two non-DMD breakpoints.

Cell Line↗
PubMed1987

Molecular heterogeneity of translocations associated with muscular dystrophy.

Individual translocation chromosomes from six girls suffering from Duchenne or Becker muscular dystrophy (DMD or BMD) have been isolated in human-mouse somatic cell hybrids. DNA prepared from these hybrids was probed with sequences physically close to the locus; these include a junction fragment from the site of the X:21 translocation (pXJ1) and subclones from the pERT 87 (DXS164) region which are absent in a minority of male DMD patients. Both sets of sequences mapped within the area defined by the translocation breakpoints, confirming their close proximity to the DMD and BMD loci. Furthermore, the X chromosome breakpoints of the translocations can be divided into three categories depending upon their position in relation to the sequences recognised by pXJ1 and pERT 87. The genomic target disrupted by the translocations examined here is a minimum of 176 kb.

Chromosome Mapping↗
PubMed1986

Muscular dystrophy in girls with X;autosome translocations.

Twenty known cases of X;autosome translocations with breakpoints at Xp21 associated with Duchenne or Becker muscular dystrophy in girls are reviewed. The variable severity described for different persons may reflect differences in X inactivation or in the nature of the genomic target disrupted. High resolution cytogenetic studies on 12 cases indicate breakpoints on the X chromosome at Xp21.1 or Xp21.2. Translocation chromosomes from several of these cases have been isolated in human/mouse somatic cell hybrids. Molecular heterogeneity in the breakpoint positions has been established by probing DNA from these hybrids with a range of cloned sequences known to be located within, or closely linked to, the Duchenne region. The minimum separation between the most distal and the most proximal breakpoints is 176 kb suggesting that, if a single gene is involved, it must be large. Alternatively, the translocations may affect different genes, or confer alterations to regulatory sequences which operate at a distance.

Chromosome Banding↗
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↗