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T L Yang-Feng

Publications and source records attributed to T L Yang-Feng.

108 records · Page 6Linked to original sources
PubMed1986

Localization of the LDHA gene to 11p14----11p15 by in situ hybridization of an LDHA cDNA probe to two translocations with breakpoints in 11p13.

Lymphoblastoid cell lines established from two individuals with apparently balanced translocations involving 11p13 were used for LDHA regional localization. The karyotypes were 46,XY,t(4;11)(q21;p13) and 46,XY,t(1;11)(p22;p13). In situ hybridization of a human LDHA cDNA probe to chromosome preparations from these cell lines resulted in specific labeling over bands p14----p15 of the normal chromosomes 11 and over bands 11p14----11p15 of the derivative chromosomes 4 and 1. These results exclude LDHA from any region proximal to 11p13 and localize the gene to 11p14----11p15.

Cell Line↗
PubMed1986

The human tyrosine aminotransferase gene mapped to the long arm of chromosome 16 (region 16q22----q24) by somatic cell hybrid analysis and in situ hybridization.

Tyrosine aminotransferase (TAT; EC 2.6.1.5) is a liver enzyme involved in amino acid metabolism and gluconeogenesis. Low levels of TAT have been implicated in several inherited disorders, particularly tyrosinemia II (Richner-Hanhart syndrome). We have determined the chromosomal location of the human TAT gene by Southern blot hybridization analysis of DNAs from 18 human X rodent hybrid cell lines, using a rat cDNA probe. The results indicate that the TAT gene maps to chromosome 16. Analysis of two hybrids containing a rearranged chromosome 16 allowed assignment of the TAT locus to 16q22----24. In situ hybridization to human metaphase chromosomes confirmed this regional assignment.

Animals↗
PubMed1986

Human luteinizing hormone-releasing hormone gene (LHRH) is located on short arm of chromosome 8 (region 8p11.2----p21).

Luteinizing hormone-releasing hormone (LHRH) is synthesized by hypothalamic neurons and affects the release of gonadotropic hormones from the anterior pituitary gland. A cDNA clone encoding the human LHRH precursor molecule was used to assign the LHRH gene to a human chromosome by in situ hybridization and Southern blot analysis. Metaphase spreads from two normal individuals were hybridized with 3H-labeled LHRH-specific sequence. Of 120 cells analyzed, 33 had silver grains over the p11.2----p21 bands of chromosome 8. No other chromosomal site was labeled above background, indicating the presence of a single site for LHRH sequences in the human genome. Independent confirmation for this location of the human LHRH gene on chromosome 8p was provided by analysis of DNA from human X Chinese hamster somatic cell hybrids. DNA samples were digested with EcoRI, blotted, and hybridized with the 32P-labeled human LHRH precursor cDNA probe. The single 11.5-kb human-specific band was detected only in hybrids containing human chromosome 8. Also, hybridization was observed in DNA from hybrids in which a portion of human chromosome 8 (region 8pter----8q21) had been spontaneously translocated onto a Chinese hamster chromosome.

Animals↗
PubMed1986

Molecular cloning of cDNAs encoding rat and human medium-chain acyl-CoA dehydrogenase and assignment of the gene to human chromosome 1.

Rat liver mRNA encoding the precursor of medium-chain acyl-CoA dehydrogenase was purified to near homogeneity by polysome immunoadsorption using a polyclonal, monospecific antibody. A single-stranded, 32P-labeled cDNA probe was synthesized using the enriched mRNA as template and was used to screen directly 15,000 colonies from a total rat liver cDNA library constructed in pBR322. One clone [600 base pairs (bp)] was positively identified by hybrid-selected translation combined with mitochondrial processing of translated products. Using the isolated rat cDNA as probe, 43,000 colonies from a human liver cDNA library were screened. Three overlapping clones (1100 bp, 500 bp, and 400 bp) were isolated and positively identified by hybrid-selected translation. The largest human cDNA clone was subcloned into the transcription vector pGEM-2, which contains a bacteriophage T7 RNA polymerase promoter. In vitro transcription of this recombinant, followed by in vitro translation, showed that the cDNA clone coded for approximately 80% of the medium-chain acyl-CoA dehydrogenase protein. The sizes of rat and human mRNAs encoding the precursor of medium-chain acyl-CoA dehydrogenase were 2.2 and 2.4 kilobases long, respectively, as determined by blot hybridization analysis of electrophoretically fractionated poly(A)+ RNA. Southern blot analysis of DNAs from human-rodent somatic cell hybrids with an isolated human cDNA assigned the gene coding for this enzyme to the short arm of chromosome 1, band p31. The chromosomal assignment was confirmed by in situ hybridization of the probe to human metaphase cells. Direct screening of cDNA libraries using a highly enriched mRNA to generate a probe, as demonstrated in this study, may provide the most rapid and convenient approach to cDNA cloning of low-abundance mRNAs.

Acyl-CoA Dehydrogenase↗
PubMed1986

Genes for synapsin I, a neuronal phosphoprotein, map to conserved regions of human and murine X chromosomes.

Synapsin I is a neuron-specific phosphoprotein associated with the membranes of small synaptic vesicles. Its function is not entirely clear, but evidence points to a possible role in the regulation of neurotransmitter release. Its biosynthesis is under developmental control. Assignment of the human synapsin I gene to the X chromosome at band Xp11 was accomplished by in situ hybridization, using a rat cDNA probe. Southern blot analysis of DNAs from a panel of human-Chinese hamster somatic cell hybrids with defined regions of the human X chromosome confirmed the in situ mapping data. The mouse synapsin I gene was assigned to the X chromosome, proximal to band XD, by Southern blot analysis of Chinese hamster-mouse somatic cell hybrids with normal or rearranged mouse X chromosomes. In situ chromosomal hybridization experiments localized the mouse synapsin I gene more precisely to bands XA1----A4. These results add to the comparative gene map of mammalian species and support certain hypotheses regarding the evolutionary relationship between human and mouse X chromosomes. We hypothesize that the synapsin I gene could be mutated in human X-linked disorders with primary neuronal degeneration, such as the Rett syndrome.

Animals↗
PubMed1986

Cloning and screening with nanogram amounts of immunopurified mRNAs: cDNA cloning and chromosomal mapping of cystathionine beta-synthase and the beta subunit of propionyl-CoA carboxylase.

We have developed conditions for efficient cDNA cloning of nanogram amounts of purified mRNAs coding for cystathionine beta-synthase [L-serine hydro-lyase (adding homocysteine), EC 4.2.1.22] and for the cytosolic precursors of mitochondrial ornithine transcarbamylase (carbamoylphosphate:L-ornithine carbamoyltransferase, EC 2.1.3.3) and the beta subunit of propionyl-CoA carboxylase [propanoyl-CoA: carbon-dioxide ligase (ADP-forming), EC 6.4.1.3]. The three mRNAs, prepared by sequential immunoselection from the same batch of rat liver polysomes, were pooled (20 ng each), and cDNA was synthesized by using avian reverse transcriptase. The second DNA strand was prepared by "nick-translation repair" of the cDNA . mRNA hybrid with RNase H, polymerase I, and DNA ligase from Escherichia coli. The double-stranded (ds) DNA was tailed with deoxycytidine residues, annealed with Pst I-cut/dG-tailed pBR322, and used to transform E. coli. The library generated by this three-step procedure contained 5000 independent colonies. A 550-base-pair (bp) cDNA clone of the beta subunit of propionyl-CoA carboxylase was detected by hybrid-selected translation; it was then used to screen the library for longer cDNAs. Two hybridizing cDNAs, 1200 and 1000 bp long with a 200-bp overlap, representing together a full-length copy of the coding region and 446 bp of 3' untranslated sequence, were recovered. Each plasmid mapped to the region q13.3----q22 of human chromosome 3. Cystathionine beta-synthase clones were obtained by screening the library with a single-stranded [32P]cDNA prepared directly from the highly purified synthase mRNA by reverse transcriptase. The longest hybridizing cDNA of 1700 bp was used in hybrid-selected translation and detected a polypeptide of 63 kDa, identical in size to rat liver synthase. In situ hybridization of this cDNA to q22 of human chromosome 21 confirmed two previous tentative assignments of the synthase locus to this chromosome.

Animals↗
PubMed1986

The terminal deoxynucleotidyltransferase gene is located on human chromosome 10 (10q23----q24) and on mouse chromosome 19.

Terminal deoxynucleotidyltransferase (TdT) is a DNA polymerase expressed in immature lymphocytes of the thymus and bone marrow, as well as certain leukemic cells. Chromosomal assignment of the gene coding for human TdT was accomplished by in situ hybridization of a 3H-labeled cDNA probe to human chromosome preparations and by Southern blot analysis of somatic cell hybrid DNAs. The human TdT gene was mapped to the region q23----q24 of chromosome 10. Breaks at this site have been reported in different translocations in human leukemias. The mouse TdT gene was assigned to chromosome 19 by Southern blot analysis of mouse X Chinese hamster somatic cell hybrids. This result adds a fourth locus to the conserved syntenic group on mouse chromosome 19 and human chromosome 10.

Animals↗
PubMed1986

Human tissue-type plasminogen activator gene located near chromosomal breakpoint in myeloproliferative disorder.

Plasminogen activators (PA) convert the inactive proenzyme plasminogen into plasmin, which is involved in the process of fibrinolysis, tissue remodeling, and cell migration. There are two distinct forms of PA: urokinase (u-PA) and tissue-type plasminogen activator (t-PA). t-PA has higher affinity for fibrin and is the main form involved in thrombolysis. By in situ chromosomal hybridization and Southern blot analysis of somatic cell hybrid DNA, we have assigned the human t-PA gene to chromosome 8, bands 8p12----q11.2. We have detected a common EcoRI restriction fragment length polymorphism within the t-PA gene that thus provides a precisely localized highly informative marker for genetic linkage studies. The t-PA gene localization coincides with a translocation breakpoint observed in myeloproliferative disorders. Whereas leukemic cells usually secrete both types of PA, a correlation exists between acute myeloid leukemic cells that release only t-PA and failure to respond to chemotherapy.

Animals↗
PubMed1985

Tyrosine kinase receptor with extensive homology to EGF receptor shares chromosomal location with neu oncogene.

A novel potential cell surface receptor of the tyrosine kinase gene family has been identified and characterized by molecular cloning. Its primary sequence is very similar to that of the human epidermal growth factor receptor and the v-erbB oncogene product; the chromosomal location of the gene for this protein is coincident with the neu oncogene, which suggests that the two genes may be identical.

Animals↗
PubMed1985

The neu gene: an erbB-homologous gene distinct from and unlinked to the gene encoding the EGF receptor.

The neu oncogene, identified in ethylnitrosourea-induced rat neuroglioblastomas, had strong homology with the erbB gene that encodes the epidermal growth factor receptor. This homology was limited to the region of erbB encoding the tyrosine kinase domain. It was concluded that the neu gene is a distinct novel gene, as it is not coamplified with sequences encoding the EGF receptor in the genome of the A431 tumor line and it maps to human chromosome 17.

Animals↗
PubMed1985

Gene for human insulin receptor: localization to site on chromosome 19 involved in pre-B-cell leukemia.

Consistent chromosomal translocations in neoplastic cells may alter the expression of proto-oncogenes that are located near the breakpoints. The complementary DNA sequence of the human insulin receptor is similar to those of the EGF receptor (erbB oncogene) and products of the src family of oncogenes. With in situ hybridization and Southern blot analysis of somatic cell hybrid DNA, the human insulin receptor gene was mapped to the distal short arm of chromosome 19 (bands p13.2----p13.3), a site involved in a nonrandom translocation in pre-B-cell acute leukemia.

Animals↗
PubMed1985

High resolution cytogenetic evaluation of couples with recurring fetal wastage.

Both high resolution and routine chromosome analyses were used to study couples with a history of two or more spontaneous abortions in early pregnancy. In the 20 couples studied, two of the women were found to have an inversion. One paracentric inversion, (13)(q13.1q22.3), was apparent on routine analysis. The small pericentric inversion (11)(p11.12q12.3), was only detected by high resolution techniques. Given the low yield and increased cost and effort involved, we do not believe that high resolution studies are justified for screening couples with repeated abortions.

Abortion, Habitual↗
PubMed1985

The pronatriodilatin gene is located on the distal short arm of human chromosome 1 and on mouse chromosome 4.

Atrial natriuretic factors (ANF) are polypeptides having natriuretic, diuretic, and smooth muscle-relaxing activities that are synthesized from a single larger precursor: pronatriodilatin. Chromosomal assignment of the gene coding for human pronatriodilatin was accomplished by in situ hybridization of a [3H]-labeled pronatriodilatin probe to human chromosome preparations and by Southern blot analysis of somatic cell hybrid DNAs with normal and rearranged chromosomes 1. The human pronatriodilatin gene was mapped to the distal short arm of chromosome 1, in band 1p36. Southern blot analysis of mouse X Chinese hamster somatic cell hybrids was used to assign the mouse pronatriodilatin gene to chromosome 4. This assignment adds another locus to the conserved syntenic group of homologous genes located on the distal half of the short arm of human chromosome 1 and on mouse chromosome 4.

Animals↗
PubMedDate not supplied

Structure of the receptor for platelet-derived growth factor helps define a family of closely related growth factor receptors.

The primary structure of the receptor for platelet-derived growth factor (PDGF), determined by means of cloning a cDNA that encodes the murine pre-PDGF receptor, is closely related to that of the v-kit oncogene product and the receptor for macrophage colony stimulating factor (CSF-1). Common structural features include the presence of long sequences that interrupt the tyrosine-specific protein kinase domains of each molecule. The PDGF and CSF-1 receptors also share a characteristic distribution of extracellular cysteine residues. Ubiquitin is covalently bound to the purified PDGF receptor, the human gene for which is on chromosome 5.

Amino Acid Sequence↗
PubMedDate not supplied

Early detection of ovarian cancer: background, rationale, and structure of the Yale Early Detection Program.

Ovarian cancer has received national attention as a highly virulent disease. Its lack of early warning symptoms and the failure to develop highly sensitive screening tests have led some physicians to recommend prophylactic oophorectomies to women with relatives who have had ovarian cancer. Others have recommended routine screening of otherwise normal women for CA 125, a circulating tumor marker, and ultrasound examinations. Each of these techniques is associated with substantial false-positive rates that could lead to unnecessary surgery. A review of epidemiologic data suggests that familial ovarian cancer kindreds are rare, but women with first-degree relatives who have had ovarian cancer have a significant risk themselves for developing ovarian cancer. In addition, women with a great number of ovulatory cycles are at an increased risk for the disease. Circulating tumor markers are frequently elevated in women with advanced ovarian cancer, but their value in early detection of ovarian cancer has yet to be established. Advances in endovaginal ultrasound and color Doppler flow technology have significantly improved our ability to assess pelvic organs. This article presents the background, rationale, and structure of the Yale Early Detection Program for ovarian cancer, whose goals are to identify the best techniques for diagnosing ovarian cancer in an early stage, to determine the frequency with which such tests should be employed, to assess false-positive results, and to identify women who might benefit from prophylactic oophorectomies.

Biomarkers, Tumor↗
PubMedDate not supplied

Early detection of ovarian cancer: preliminary results of the Yale Early Detection Program.

Eighty-four women at high risk for ovarian cancer by having first-degree relatives with epithelial ovarian cancer participated in a newly established, early ovarian cancer detection program at Yale University. Participants were to be evaluated with physical examinations and circulating tumor markers at entry and every six months thereafter. Endovaginal ultrasound and color Doppler flow studies were to be performed at three and nine months following entry into the program. In addition, women were encouraged to follow American Cancer Society guidelines for mammography. Stool was checked for occult blood. Endometrial sampling was offered to post-menopausal women. No participant has developed an ovarian cancer since entering the program. One woman has been diagnosed to have breast cancer. False-positive levels of circulating tumor markers (CA 125, 4/84 [4.8 percent]; lipid-associated sialic acid in plasma, 13/84 [15.5 percent]; NB/70K, 4/84 [4.8 percent]; and urinary gonadotropin fragment, 1/65 [1.5 percent]) were observed on entry into the program. Low resistive indices (less than 0.5) were documented in 8/91 (8.8 percent) ovaries studied by the color Doppler flow technique. One participant underwent a laparotomy based on a false-positive endovaginal ultrasound examination. Tests now being employed in community practice have a high likelihood of being associated with false-positive results. Therapeutic interventions based on isolated abnormal tumor markers or ultrasound studies obtained from women with family histories of ovarian cancer may lead to inappropriate surgery. It is necessary for cancer centers to develop expertise in ovarian cancer detection techniques to advise physicians in their geographic areas appropriately about the significance of the abnormal screening test.

Adult↗