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Biomedical subjects

M Ferguson-Smith

Publications and source records attributed to M Ferguson-Smith.

18 recordsLinked to original sources
PubMed2001

Cross-species color banding in ten cases of myeloid malignancies with complex karyotypes.

Cross-species color banding is a multiple-color fluorescence in situ hybridization (FISH) technique using probes developed from other animal species. Hybridization to human metaphases produces color banding patterns specific for each homologous chromosome pair. The technique has been evaluated in a complementary manner with G-banding and chromosome painting in a series of 10 myeloid malignancies with complex or unresolved karyotypes. Color banding detected the majority of chromosomal abnormalities, which had been identified by G-banding and in each case revealed chromosomal changes that G-banding had not identified. Painting was necessary to confirm these abnormalities due to the limitation of only seven colors in the color-banded karyotype. At the same time, painting fortuitously uncovered cryptic abnormalities in 6 of 10 cases that had not been detected by color banding. Insertions were visible by painting only. This study has demonstrated that in the analysis of complex karyotypes, the application of color banding revealed the involvement of the long arm of chromosome 3, indicating a poor risk, in two cases not identified by G-banding. Therefore, these techniques applied together have revealed cryptic chromosomal abnormalities with prognostic significance, which in some cases may have implications for patient management.

Adolescent↗
PubMed2001

Chromosomal positioning of human T-lymphotropic type 1 proviruses by fluorescence in situ hybridisation.

Fluorescence in situ hybridisation (FISH) was employed to identify the chromosomal integration site of the human T-cell lymphotropic virus, type 1 (HTLV-1) present in T-cell clones derived from HTLV-1-infected individuals and a virally transformed cell line, C8166-45. Proviral sequences were detected in C8166-45 but not uninfected Jurkat cells. Integration sites were reliably detected in T-cell clones determined previously to be infected with HTLV-1. The results indicated that the transformed cell line and some of the T-cell clones possessed more than one proviral integration site. This hybridisation system is useful for determining the number of integration events and for localising proviruses to specific chromosomal regions.

Cell Line, Transformed↗
PubMed2001

Reciprocal chromosome painting between a New World primate, the woolly monkey, and humans.

We employed fluorescence-activated chromosome sorting (FACS) to construct chromosome paint sets for the woolly monkey (Lagothrix lagotricha) and then FISH to reciprocally paint human and woolly monkey metaphases. Reciprocal chromosome painting between humans and the woolly monkey allowed us to assign subchromosomal homologies between these species. The reciprocal painting data between humans and the woolly monkey also allow a better interpretation of the chromosomal difference between humans and platyrrhines, and refine hypotheses about the genomic rearrangements that gave origin to the genome of New World monkeys. Paints of woolly monkey chromosomes were used to paint human metaphases and forty-five clear signals were detected. Paints specific to each human chromosome were used to paint woolly monkey metaphases. The 23 human paints gave 39 clear signals on the woolly monkey karyotype. The woolly monkey chromosomes painted by human paints produced 7 associations of segments homologous to human chromosomes or human chromosome segments: 2/16, 3/21, 4/15, 5/7, 8/18, 10/16 and 14/15. A derived translocation between segments homologous to human chromosomes 4 and 15 is a synapomorphic marker linking all Atelines. These species may also be linked by fragmentation of homologs to human 1, 4, and 15.

Animals↗
PubMed2000

A new submicroscopic deletion that refines the 9p region for sex reversal.

Male to female sex reversal has been described in patients with deletions of chromosome 9p, and a region critical for sex reversal has been localized to p24.3, at the tip of the chromosome (TD9). It was proposed that the sex reversal may arise by haploinsufficiency for a gene localized to the minimum deletion. The 9p24.3 genes DMRT1 and DMRT2 are the favorite TD9 candidates to date, in virtue of their sequence similarity to doublesex and mab-3, sexual regulators in Drosophila and Caenorhabditis elegans, respectively. The hypothesis of sex reversal by combined haploinsufficiency for the two genes was put forward to explain the lack of mutations in either gene in XY sex-reversed females. Here we describe a XY sex-reversed patient carrying a novel 9p deletion that extends over less than 700 kb of genomic DNA. This region defines the smallest interval for sex reversal found to date. DMRT1 and DMRT2 map outside this region. Our data do not support the hypothesis of combined haploinsufficiency for DMRT1 and DMRT2. Nevertheless, DMRT1 localizes very close to the deletion breakpoint and has a pattern of expression compatible with a role in sex determination. It therefore remains a candidate gene for 9p sex reversal.

Amino Acid Sequence↗
PubMed2000

Multiplex fluorescence in situ hybridization and cross species color banding of a case of chronic myeloid leukemia in blastic crisis with a complex Philadelphia translocation.

Exciting new techniques in molecular cytogenetics--namely, spectral karyotyping, multiplex fluorescence in situ hybridization (M-FISH), and cross species color banding--have been recently developed. An increasing number of reports demonstrate the success of these procedures in providing additional cytogenetic information--identifying marker chromosomes and revealing the presence of previously undetected chromosomal changes. However, these procedures have their limitations, and their absolute sensitivity in the accurate identification of subtle chromosomal abnormalities remains to be established. M-FISH and color banding have been applied to a case of chronic myeloid leukemia with a complex Philadelphia translocation involving chromosomes 9, 17, and 22, which had initially been identified from G-banded chromosome analysis. The abnormalities were confirmed by chromosome "painting" and specific probes. Although M-FISH and color banding revealed no additional cryptic chromosomal changes, this study has clearly demonstrated the success of these multiple color FISH approaches in the accurate characterization of a complex rearrangement with subtle abnormalities.

Adolescent↗
PubMed1999

Micro- and macrochromosome paints generated by flow cytometry and microdissection: tools for mapping the chicken genome.

Despite the chicken being one of the most genetically mapped of all animals, its karyotype remains poorly defined. This is primarily due to microchromosomes that belie assignment by conventional methods. To address this problem, we have developed chromosome-specific paints using flow cytometry and microdissection. For the microchromosomes it was necessary to amplify and label DNA from single microdissected chromosomes.

Animals↗
PubMed1995

Chromosome specific paints from a high resolution flow karyotype of the mouse.

Chromosomes from antigen stimulated B-cells from spleens of inbred mice have been separated using flow cytometry into 18 distinguishable peaks. Using locus-specific oligonucleotides and fluorescence in situ hybridization to banded metaphase spreads, 15 individual chromosomes were identified: 1, 2, 3, 6, 7, 8, 9, 11, 12, 16, 17, 18, 19, X and Y. The remaining six chromosomes, occurring as pairs in three peaks, 4 with 5, 10 with 13, and 14 with 15, were resolved by flow sorting chromosomes from mice carrying an appropriate homozygous translocation and 4, 5 and 14 have been isolated in this way. This is the first demonstration of how a complete set of mouse chromosome paints can be produced.

Animals↗
PubMed1993

Structure and expression analysis of a member of the human glutamate dehydrogenase (GLUD) gene family mapped to chromosome 10p11.2.

Glutamate dehydrogenase (GLUD) is a key metabolic enzyme of the mitochondrion, playing an important role in mammalian neuronal transmission. GLUD deficiency has been associated with certain forms of neurodegeneration in the human cerebellum. Genomic DNA blot hybridization analysis and identification of a large number of GLUD-specific genomic clones have suggested that human GLUD is encoded by a multigene family consisting of at least six members. A functional GLUD gene, GLUD1, has been mapped to chromosome 10q22.3-23 and a full-length "processed" GLUD gene, GLUDP1, to chromosome Xq22-23. In the context of studing the structure, the role, and the chromosomal organization of the other family members, we have analysed in detail, a cosmid clone solely reactive with the 3' region of the GLUD cDNA. Structure and expression analysis of its GLUD-specific region suggests that it represents a truncated "processed" GLUD pseudogene. Fluorescence in situ hybridization using the entire cosmid as a probe, mapped this GLUD gene locus, termed GLUDP5, to chromosome 10p11.2.

Amino Acid Sequence↗
PubMed1993

A G-->A substitution in an HNF I binding site in the human alpha-fetoprotein gene is associated with hereditary persistence of alpha-fetoprotein (HPAFP).

A family displaying hereditary persistence of alpha-fetoprotein (HPAFP) in adult life was detected in an antenatal screening programme for spina bifida. RFLP linkage analysis shows that the trait is linked with the albumin-AFP locus. The molecular mechanism responsible for the post-natal repression of the AFP gene is unknown. We wished to determine the molecular mechanism underlying HPAFP in this family. Sequence analysis of the 5'-flanking sequences of their gene revealed a GA substitution at position -119 associated with the trait. This substitution occurs in a potential HNF I binding site, and increases the similarity of the sequence to a consensus HNF I recognition site. In a competitive gel retardation assay the mutant sequence binds HNF I alpha more tightly than the wild type sequence. Furthermore, 5'-flanking sequences of the human AFP gene containing the G-->A substitution direct a higher level of CAT expression in transfected human hepatoma cells than the wild type sequences. We conclude that the G-->A substitution at position -119 of the AFP gene is the mutation causing HPAFP in this family. These results highlight the importance of this HNF I binding site in the developmental regulation of the AFP gene.

Adult↗
PubMed1989

Localization of murine X and autosomal sequences homologous to the human Y located testis-determining region.

Recently a candidate gene for the primary testis-determining factor (TDF) encoding a zinc finger protein (ZFY) has been cloned from the human Y chromosome. A highly homologous X-linked copy has also been identified. Using this human sequence it is possible to identify two Y loci, an X and an autosomal locus in the mouse (Zfy-1, Zfy-2, Zfx and Zfa, respectively). Suprisingly ZFY is more homologous to the mouse X and autosomal sequences than it is to either of the Y-linked loci. Both Zfy-1 and Zfy-2 are present in the Sxr region of the Y but Zfy-2 is absent in the Sxr deletion variant Sxrb (or Sxr") suggesting it is not necessary for male determination. Extensive backcross analyses map Zfa to mouse chromosome 10 and Zfx to a 5-cM interval between anonymous X probe MDXS120 and the tabby locus (Ta). We also show that the mouse androgen receptor locus (m-AR) believed to underlie the testicular feminization mutation (Tfm) shows complete linkage to Zfx. Comparative mapping indicates that in man these genes lie in separate conserved DNA segments.

Animals↗
PubMed1988

Expression of chromosome 21 specific sequences in normal and Down's syndrome tissues.

Using RNA isolated from age and sex matched normal and Down's Syndrome foetal liver and brain tissues, Northern blots were prepared and probed with 4 chromosome 21 specific sequences. The results show that no consistent pattern of expression emerges when Down's Syndrome tissue is compared with normal tissue but the results are very different from the 3/2 ratio of expression which may be expected. Two sequences 21.3 and 26C show only minor differences in expression in trisomy 21 liver samples but significant changes in their expression pattern when normal and Down's Syndrome brain samples are compared. The other sequences, JG77 and JG90 show a 5 fold higher degree of expression in Down's brain but when liver samples are compared one of these sequences shows equal levels of expression in normal and Down's Syndrome samples and the other shows a decrease in expression level in Down's Syndrome samples.

Animals↗
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↗