PubMed Health⌕ Search

Biomedical subjects

G H Travis

Publications and source records attributed to G H Travis.

14 recordsLinked to original sources
PubMed1992

Complete rescue of photoreceptor dysplasia and degeneration in transgenic retinal degeneration slow (rds) mice.

retinal degeneration slow (rds) is a semidominant mutation of mice with the phenotype of abnormal development of rod and cone photoreceptors, followed by their slow degeneration. The rds gene has been putatively cloned and its novel protein product initially characterized biochemically. In the present study we undertook to correct in vivo the retinal phenotype of mice with the rds mutation. We assembled a transgene containing a regulatory segment of the opsin gene positioned upstream of the wild-type rds coding region. Mice from three transgenic lines, homozygous for the rds mutation, were analyzed for expression of the transgene and for their retinal phenotypes. In two high expressing lines, we observed complete reversion to wild-type retinal morphology. In a third, low expressing line, we observed a retinal phenotype intermediate between wild type and rds/rds, suggesting partial rescue of the mutation. These results constitute formal proof that we have cloned the rds gene.

Animals↗
PubMed1991

Mutations in the human retinal degeneration slow gene in autosomal dominant retinitis pigmentosa.

The murine retinal degeneration slow (rds) gene is a semidominant mutation with a phenotype having rod and cone photoreceptors that develop abnormally and then slowly degenerate. The phenotype is a possible model for retinitis pigmentosa, one of the scores of hereditary human retinal degenerations, which is also characterized by photoreceptor degeneration. We report here three mutations of the human homologue of the rds gene (RDS) that cosegregate with autosomal dominant retinitis pigmentosa in separate families. Our results indicate that some cases of autosomal dominant retinitis pigmentosa are due to mutations at the RDS locus.

Adult↗
PubMed1991

Name dropping.

Explore the source record for details and available documents.

Intermediate Filament Proteins↗
PubMed1991

The human retinal degeneration slow (RDS) gene: chromosome assignment and structure of the mRNA.

Retinal degeneration slow (rds) is a mouse neurological mutation that is characterized phenotypically by abnormal development of rod and cone photoreceptors followed by their slow degeneration. This phenotype resembles the pathologic abnormalities seen in retinitis pigmentosa. The mouse rds gene has recently been cloned. Here we present the sequence of a full-length cDNA clone of the human RDS mRNA. We show that in human retina there are two RDS transcripts of 3.0 and 5.5 kb. By analysis of DNA from a panel of human X hamster somatic cell hybrids, and by direct in situ hybridization, we show that the RDS gene is located on the proximal short arm of human chromosome 6. Finally, we present information on the frequency of several observed restriction fragment length polymorphisms using the RDS cDNA. This information is of potential value for testing linkage of the RDS gene to the disease phenotype in families with retinitis pigmentosa.

Amino Acid Sequence↗
PubMed1991

The retinal degeneration slow (rds) gene product is a photoreceptor disc membrane-associated glycoprotein.

Mice homozygous for the retinal degeneration slow (rds) mutation exhibit abnormal development of photoreceptor cells, followed by their slow degeneration. We have recently cloned the rds gene and determined the structure of the wild-type rds mRNA. Here we show that the gene is expressed exclusively in photoreceptor cells. We demonstrate that it encodes a 39 kd membrane-associated glycoprotein that is restricted to photoreceptor outer segments. By electron microscopy, we show that the rds protein is distributed uniformly within outer segment discs. The developmental appearance of the rds protein coincides with outer segment disc formation. We propose that the rds protein functions as an adhesion molecule for stabilization of the outer segment discs.

Amino Acid Sequence↗
PubMed1990

Patterns of cerebral cortex mRNA expression.

A pool of 163 clones, isolated by screening 60,000 members of a Macaca fascicularis cerebral cortex cDNA library with a cortex-minus-cerebellum subtracted probe prepared by the phenol enhancement method, was analyzed by Northern blot hybridization studies. One hundred fifty-three of these clones corresponded to 22 RNAs whose abundance was at least 2-fold higher in cerebral cortex poly(A)+ RNA samples than in samples of cerebellar poly(A)+ RNA. Seven of these RNAs, represented by 131 clones, were undetectable in cerebellum. Only 10 of the 163 clones proved to be false positives. The abundance of several of these cortex-enriched RNAs was altered in Alzheimer's disease brains. Several RNAs that were present in cerebral cortex but undetectable in cerebellum were generally enriched in telencephalon, although none was restricted to the cortex. One of the cortex enriched RNAs, whose nucleotide sequence is presented, encoded monkey preprocholecystokinin. Overall, this study provides insights into the powers and limitations of subtractive hybridization and into the patterns of gene expression in the central nervous system.

Alzheimer Disease↗
PubMed1990

Isolation and characterization of Borna disease agent cDNA clones.

Borna disease (BD) is a neurologic syndrome characterized by behavioral disturbances and the accumulation of specific proteins in limbic system neurons. A viral etiology has been proposed because BD can be induced in birds, rodents, and primates by inoculation with filtered brain homogenates from animals with BD. We report here the isolation and preliminary characterization of cDNA clones from a rat with BD. These clones hybridized to specific transcripts in BD rat brain and arrested in vitro translation of BD proteins. In situ hybridization experiments using RNA probes prepared from these clones showed an abundance of these transcripts in limbic system neurons. Northern (RNA) hybridizations using these RNA probes indicated that the BD agent is probably a virus with major transcripts of 8.5, 2.1, and 0.8 kilobases.

Animals↗
PubMed1989

Identification of a photoreceptor-specific mRNA encoded by the gene responsible for retinal degeneration slow (rds).

Mutant mice homozygous for 'retinal degeneration slow' (rds/rds) are characterized phenotypically by abnormal development of photoreceptor outer segments in the retina, followed by gradual degeneration of photoreceptors. This process of degeneration is complete by one year, with preservation of all other retinal cells. The biochemical defect that leads to the mutant phenotype is not known. Our strategy for cloning the rds gene was based upon three previously reported observations. First, the rds locus maps to chromosome 17. Second, experimental rds/rds----+/+ and rds/+----+/+ tetra-parental mice manifest patchy photoreceptor changes in the retina, suggesting that the wild-type rds locus is expressed within cells of the photoreceptor lineage. Finally, the process of degeneration is specific to photoreceptors. On the basis of these observations, we predicted that the rds mRNA is encoded by a gene on chromosome 17 and is normally expressed exclusively within photoreceptors in the retina. We here present evidence that this is the case.

Amino Acid Sequence↗
PubMed1988

Phenol emulsion-enhanced DNA-driven subtractive cDNA cloning: isolation of low-abundance monkey cortex-specific mRNAs.

To isolate cDNA clones of low-abundance mRNAs expressed in monkey cerebral cortex but absent from cerebellum, we developed an improved subtractive cDNA cloning procedure that requires only modest quantities of mRNA. Plasmid DNA from a monkey cerebellum cDNA library was hybridized in large excess to radiolabeled monkey cortex cDNA in a phenol emulsion-enhanced reaction. The unhybridized cortex cDNA was isolated by chromatography on hydroxyapatite and used to probe colonies from a monkey cortex cDNA library. Of 60,000 colonies screened, 163 clones were isolated and confirmed by colony hybridization or RNA blotting to represent mRNAs, ranging from 0.001% to 0.1% abundance, specific to or highly enriched in cerebral cortex relative to cerebellum. Clones of one medium-abundance mRNA were recovered almost quantitatively. Two of the lower-abundance mRNAs were expressed at levels reduced by a factor of 10 in Alzheimer disease relative to normal human cortex. One of these was identified as the monkey preprosomatostatin I mRNA.

Amino Acid Sequence↗
PubMed1987

Subtractive cloning of complementary DNAs and analysis of messenger RNAs with regional heterogeneous distributions in primate cortex.

Morphological heterogeneity of individual neurons in the mammalian brain must ultimately result from differences between cells in their profiles of gene expression. However, the degree to which neurons located in different regions of the brain express different sets of genes is not known. Using differential cDNA cloning procedures, including subtractive hybridization and differential colony screening, a quantitative analysis of RNAs with heterogeneous distributions in the telencephalon of the rat and Old World monkey has been performed. The results suggest that no species of RNA exist with a distribution specific to the hippocampus or neocortex of the rat with an abundance greater than 0.05%. Additionally, the results with an abundance of 0.05% or greater which is present in neocortex of the monkey but absent from the cerebellum suggest that only one species of mRNA exists. A Northern blot analysis of cDNA clones representing mRNAs present in the neocortex but absent from the cerebellum of the monkey is presented, establishing the effectiveness of subtractive hybridization between different regions of the brain for cDNA cloning. Also presented is in situ hybridization analysis of the cellular distributions in primate neocortex of two mRNAs. One of these RNAs, detected by clone 1B4 is present in cortical laminae V and VI, and exhibits a high degree of heterogeneity in the overall density of labelled cells.

Animals↗