Showing papers by "John W. Belmont published in 1992"
Journal Article•
TL;DR: The human androgen-receptor gene (HUMARA) contains a highly polymorphic trinucleotide repeat in the first exon that correlates with X inactivation, and the development of a PCR assay that distinguishes between the maternal and paternal alleles and identifies their methylation status is developed.
Abstract: The human androgen-receptor gene (HUMARA; GenBank) contains a highly polymorphic trinucleotide repeat in the first exon. We have found that the methylation of HpaII and HhaI sites less than 100 bp away from this polymorphic short tandem repeat (STR) correlates with X inactivation. The close proximity of the restriction-enzyme sites to the STR allows the development of a PCR assay that distinguishes between the maternal and paternal alleles and identifies their methylation status. The accuracy of this assay was tested on (a) DNA from hamster/human hybrid cell lines containing either an active or inactive human X chromosome; (b) DNA from normal males and females; and (c) DNA from females showing nonrandom patterns of X inactivation. Data obtained using this assay correlated substantially with those obtained using the PGK, HPRT, and M27 beta probes, which detect X inactivation patterns by Southern blot analysis. In order to demonstrate one application of this assay, we examined X inactivation patterns in the B lymphocytes of potential and obligate carriers of X-linked agammaglobulinemia.
1,659 citations
TL;DR: It is proposed that autologous marrow stromal support during the transduction period may have application in clinical gene therapy protocols.
149 citations
TL;DR: These mutations provide evidence that different mechanisms can result in galactosemia: destabilizing mutations in any given area of the protein and missense mutations in conserved domains of the enzyme resulting in low or no activity.
28 citations
TL;DR: Results were consistent with estimates of the transduction frequency based on acquisition of resistance to G418 as the number of colonies growing under G418 selection was always greater at 0.8 mg/ml G418 than at higher concentrations of G418.
Abstract: Marrow cells were exposed to the LNL6 or G1N safety-modified variants of the N2 retrovirus, which contain the G418 bacterial resistance gene neo. The frequency of acquisition of the G418 resistance phenotype following exposure to LNL6 or G1N was compared among hematopoietic progenitor cells from the marrow of patients with chronic phase chronic myelogenous leukemia (CML), blast crisis CML, or from nonleukemic individuals. Under the conditions of our experiments, the myeloid committed progenitor cells from 3 of 6 nonleukemic individuals, 9 of 18 chronic-phase CML patients, and 2 of 4 blast crisis CML patients acquired resistance to at least 1 mg/ml G418 following incubation with cell-free supernatants from the PA317 LNL6 or PA317 G1N producer cell lines. Ten of the 32 colonies growing up in 0.8 mg/ml G418 from chronic-phase marrow exposed to LNL6 were shown to contain the neo gene by polymerase chain reaction (PCR) assay of DNA. These results were consistent with estimates of the transduction freq...
20 citations
16 citations