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D S Gerhard

Publications and source records attributed to D S Gerhard.

51 records · Page 3Linked to original sources
PubMed1988

Restriction analysis of the structural alpha-L-fucosidase gene and its linkage to fucosidosis.

Human alpha-L-fucosidase is a lysosomal enzyme responsible for hydrolysis of alpha-L-fucoside linkages in fucoglycoconjugates. A single gene, FUCA 1, located on chromosome 1p34.1-1p36.1 encodes for alpha-L-fucosidase activity. To gain insight into the nature of the molecular defects leading to fucosidosis, we have characterized the genomic structure of FUCA 1. Restriction-endonuclease analysis suggests that at least seven exons dispersed over 22 kb are present in genomic FUCA 1. Two restriction-fragment-length polymorphisms (RFLPs) have been identified in the Caucasian population. The PvuII and BglI RFLPs each have two codominant alleles in Hardy-Weinberg equilibrium. Allele frequencies for the PvuII RFLP are .70/.30, and those for the BglI RFLP .63/.37. Both RFLPs are in strong linkage disequilibrium with each other, with a correlation coefficient of .94. The polymorphism information content (PIC) of the combined DNA markers is .38, high enough to be useful in the prenatal diagnosis of fucosidosis. The combined lod score for linkage between the fucosidosis mutation and FUCA 1 markers in two families was significant at a recombination fraction of 0. This suggests that the fucosidosis mutation resides in FUCA 1.

Blotting, Southern↗
PubMed1987

Analysis of human chromosome 11 by somatic cell genetics: reexamination of derivatives of human-hamster cell line J1.

Through the fusion of a CHO cell population to a human cell population, a hybrid cell line which has lost all human chromosomes except chromosome 11 was derived. This cell line, J1, does not appear to segregate human chromosome 11 during growth. A series of deletion segregants were isolated from J1 which had lost a portion of either the long, short, or both arms of chromosome 11. This panel of deletion segregants was used for mapping a number of genetic markers on the short arm of chromosome 11. Karyotypic analysis led to the interpretation that derivatives of J1 selected for the loss of cell surface antigens encoded by genes on the short arm of the chromosome had simple terminal deletions of this chromosome arm. More recently, we have applied recombinant DNA and in situ hybridization techniques to the analysis of the structure of chromosome 11. In the course of this analysis, we have obtained data that indicate that all J1 deletion segregants retain a small chromosomal segment containing the structural genes for insulin and HRAS1. Analysis of in situ hybridization data indicates that in cell lines in which a chromosome 11 fragment cannot be identified by karyotype analysis, human DNA has been translocated to a Chinese Hamster chromosome. These results suggest that the original interpretation of the karyotypes of deletion segregants derived from J1 as simple terminal deletions is not correct. A reanalysis of gene localization studies based on these deletion segregants suggests that some assignments of genes to specific bands on chromosome 11 should be reconsidered. In particular, data on additional deletion segregants are consistent with localization of the beta-globin gene complex to band 11p15. The data presented here suggest that in several hybrid derivatives of J1, a continuous DNA segment of approximately 10(7) base pairs in length which includes the insulin and HRAS1 (cellular homolog of retroviral oncogene Harvey ras) genes has been isolated from the remainder of the human genome. We propose that the stability of chromosome 11 in the original hybrid was due to complementation of a genetic defect in the original CHO cell parent by a gene located in close physical proximity to the insulin and HRAS1 genes on chromosome 11. Data are presented which test and support this hypothesis.

Animals↗
PubMed1987

Search for a gene that predisposes individuals to BPI disorder.

To determine the role of genetics in bipolar affective disorders it was necessary to have correct diagnoses and large homogenous population(s). To identify a marker linked to the disease two additional factors were important, a correct model for genetic transmission and highly polymorphic DNA markers. With the establishment of a linked marker the aim is to identify the susceptibility gene. Two approaches are the prediction of candidate genes and/or the determination of a physical map of the region.

Bipolar Disorder↗
PubMed1986

Owl monkey gene mapping: the assignment of gene loci for catalase, beta-globin gene cluster, HRAS1, insulin, and parathyroid hormone.

Using somatic cell genetics and Southern blot hybridization, we have mapped five structural genes in the owl monkey, coding for catalase (CAT), the beta-globin gene cluster (HBBC), c-Ha-ras 1 (HRAS1), insulin (INS), and parathyroid hormone (PTH). All five loci are mapped to chromosome 19 of karyotype VI (2n = 49,50) of the owl monkey; CAT, HBBC, INS, and PTH can be assigned to chromosome 4 of karyotype V (2n = 46), while CAT and HBBC can be assigned to chromosome 2 of karyotype III (2n = 53). Using in situ hybridization, the CAT gene was precisely mapped on the mid-region and the beta-globin gene cluster on the telomeric end of chromosome 2q(K-III). Our results provide significant insight into the evolutionary history of these gene loci. While these loci are separated into at least two major segments in rodents such as the mouse, our results suggest conservation of a single chromosome arm among higher primates.

Animals↗
PubMed1985

Isolation of the human insulin-like growth factor genes: insulin-like growth factor II and insulin genes are contiguous.

Overlapping recombinant clones that encompass the insulin-like growth factor (IGF) I and II genes have been isolated from a human genomic DNA library. Each gene is present once per haploid genome; the IGF-I gene spans greater than 35 kilobase pairs (kbp) and the IGF-II gene is at least 15 kbp. The exon-intron organization of these genes is similar, each having four exons, which is one more than the related insulin gene. Comparison of the restriction endonuclease cleavage maps of the IGF-II and insulin genes, including their flanking regions and hybridization with an IGF-II cDNA probe, revealed that they are adjacent to one another. The IGF-II and insulin genes have the same polarity and are separated by 12.6 kbp of intergenic DNA that includes a dispersed middle repetitive Alu sequence. The order of the genes is 5'-insulin-IGF-II-3'.

Base Sequence↗
PubMed1985

Assignment of the gene coding for the T3-delta subunit of the T3-T-cell receptor complex to the long arm of human chromosome 11 and to mouse chromosome 9.

The gene encoding the 20-kDa glycoprotein of the T3-T-cell receptor complex (T3-delta chain) has been mapped to human chromosome 11 by hybridization of a T3-delta cDNA clone (pPGBC#9) to DNA from a panel of human-rodent somatic cell hybrids. In Southern blotting experiments with DNAs of somatic cell hybrids that contained segments of chromosome 11, we were able to assign the T3-delta gene to the distal portion of the long arm of human chromosome 11 (11q23-11qter). By use of a newly developed cDNA clone (pPEM-T3 delta) that codes for the murine T3-delta chain, the mouse T3-delta gene was mapped on chromosome 9. The importance of the T3-delta map position and its relationship to the other genes on the long arm of human chromosome 11 and to those on mouse chromosome 9 is discussed.

Animals↗
PubMed1984

Identification of a recent recombination event within the human beta-globin gene cluster.

In a detailed study of inheritance of DNA sequence polymorphism in a large reference pedigree, an individual was identified with an apparent genetic recombination event within the human beta-globin gene cluster. Analysis of the haplotypes of relevant individuals within this pedigree suggested that the meiotic crossing-over event is likely to have occurred within a 19.8-kilobase-pair region of the beta-globin gene cluster. Analysis of other DNA markers closely linked to the beta-globin gene cluster--segment 12 of chromosome 11 (D11S12) and loci for insulin, the cellular oncogene c-Ha-ras, and preproparathyroid hormone--confirmed that a crossover event must have occurred within the region of chromosome 11 between D11S12 and the beta-globin gene cluster. It is suggested that the event observed has occurred within a DNA region compatible with recombinational "hot spots" suggested by population studies.

Alleles↗
PubMed1984

The prolactin gene, but not the growth hormone gene, is located on chromosome 9 in the rat.

Experiments from a number of laboratories, employing clonal lines of rat pituitary tumor cells (GH cells), have shown that the cellular levels of the mRNAs for prolactin and growth hormone are subject to regulation by a variety of hormones and other factors. To provide a framework for further studies of the regulation of the expression of these two genes, we have studied their chromosomal locations in the rat, employing our recently developed technique for identifying a unique gene by direct hybridization in situ with a 125I-labeled cDNA plasmid. A rat prolactin cDNA plasmid ( pPRL -1) yielded a signal significantly above that expected on a random basis over chromosomes 9 and 15 from rat FRE cells. Both chromosomes exhibited a subchromosomal clustering of silver grains near the telomere of chromosome 9 and on the short arm of chromosome 15. Control experiments with plasmid pBR322 also yielded a significant signal clustered over the short arm of chromosome 15. Hence, we conclude that chromosome 15 contains sequences homologous to pBR322 and that the prolactin gene is located near the telomere of chromosome 9 in the rat. A rat growth hormone cDNA plasmid (pBR322-GH1) yielded a signal above that expected on a random basis over FRE cell chromosomes 7, 13, and 15, although the labeling was poorer than with prolactin. The signal over chromosome 15 is probably due to sequences homologous to plasmid pBR322. The signals over chromosomes 7 and 13 showed a clear subchromosomal clustering near the centromere on chromosome 7 and near the telomere on the long arm of chromosome 13.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1981

Localization of a unique gene by direct hybridization in situ.

Previous determination of the chromosomal location of unique genes have required that the chromosomes of interest be fractionated, either by species-specific chromosome loss from interspecies hybrids, or by physical fractionation procedures. We have developed a general technique for the localization of a unique gene, which requires no prior chromosome fractionation. The technique involves the use of a labeled hybrid cDNA plasmid for direct hybridization in situ to metaphase cells from the organism under investigation. As a model system for development of this technique, we have employed a human alpha-globin cDNA plasmid (JW101) to localize the corresponding gene cluster. To obtain a sufficiently large autoradiographic signal, we have both labeled this plasmid with 125I to a high specific activity (10(9) dpm/micrograms) and taken advantage of the ability of a double-stranded probe to form networks. To obtain sufficient hybridization specificity, various experimental procedures were used, the most important of which was the choice from among a range of probe concentrations of the highest that does not yield excessive background hybridization. We have shown that, with an autoradiographic exposure time of only 12 days, use of this technique correctly localized the human alpha-globin gene cluster to chromosome 16. This technique should be generally applicable to the localization of any gene for which a corresponding cDNA hybrid plasmid is available.

Chromosome Mapping↗
PubMed1981

Generation of transforming viruses in cultures of chicken fibroblasts infected with an avian leukosis virus.

During serial passages of an avian leukosis virus (the transformation-defective, src deletion mutant of Bratislava 77 avian sarcoma virus, designated tdB77) in chicken embryo fibroblasts, viruses which transformed chicken embryo fibroblasts in vitro emerged. Chicken embryo fibroblasts infected with these viruses (SK770 and Sk780) had a distinctive morphology, formed foci in monolayer cultures, and grew independent of anchorage in semisolid agar. Bone marrow cells were not transformed by these viruses. Another virus (SK790) with similar properties emerged during serial subcultures of chicken embryo fibroblasts after a single infection with tdB77. The 50S to RNAs isolated from these viruses contained a tdB77-sized genome (7.6 kilobases), 8.7- and 5.7-kilobase RNAs, and either a 4.1-kilobase RNA or a 4.6-kilobase RNA. These RNAs did not hybridize with cDNA's representing the src, erb, mac, and myb genes of avian acute transforming viruses. Cells transformed by any one of the Sk viruses (SK770, SK780, or SK790) synthesized two novel gag-related polyproteins having molecular weights of 110,000 (p110) and 125,000 (p125). We investigated the compositions of these proteins with monospecific antiviral protein sera. We found that p110 was a gag-pol fusion protein which contained antigenic determinants, leaving 49,000 daltons which was antigenically unrelated to the structural and replicative proteins of avian leukosis viruses. An analysis of the SK viral RNAs with specific DNA probes indicated that the 5.7-kilobase RNA contained gag sequences but lacked pol sequences and, therefore, probably encoded p125. The transforming ability, the deleted genome, and the induced polyproteins of the SK viruses were reminiscent of the properties of several replication-defective acute transforming viruses.

Animals↗
PubMedDate not supplied

Evidence against Ha-ras-1 involvement in sporadic and familial melanoma.

It was recently reported that different rare alleles at the Ha-ras-1 locus occurred at a significantly higher combined frequency in cancer patients than in an unaffected population. In particular, melanoma patients were reported to have a significantly higher frequency of such alleles. We have examined the frequency of rare Ha-ras-1 alleles in a large number of cases of sporadic melanoma. Our results indicate that the distribution of rare alleles in this population does not differ from that found in normal populations. Also, to test the hypothesis that a hereditary predisposition to melanoma could be inherited via an allele at the Ha-ras-1 locus, we examined the transmission of the segment of the short arm of chromosome 11 (11p) carrying the Ha-ras-1 locus in a number of families previously shown to exhibit a hereditary predisposition to melanoma and its precursor lesion, the dysplastic nevus syndrome (DNS). Our genetic linkage results thus obtained strongly exclude the association of a predisposition to melanoma or the precursor lesion with the inheritance of the Ha-ras-1 locus or the segment of chromosome 11 on which it is located. These results imply that hereditary predisposition to melanoma is associated with genes other than the Ha-ras-1 locus, contradicting the original suggestion of Krontiris et al., made on the basis of either an inadequate sample size or other misleading experimental factors.

Alleles↗
PubMedDate not supplied

Bipolar affective disorders linked to DNA markers on chromosome 11.

An analysis of the segregation of restriction fragment length polymorphisms in an Old Order Amish pedigree has made it possible to localize a dominant gene conferring a strong predisposition to manic depressive disease to the tip of the short arm of chromosome 11.

Adolescent↗