The nerve growth factor receptor gene is at human chromosome region 17q12-17q22, distal to the chromosome 17 breakpoint in acute leukemias

Construction of a genetic map of human chromosome 17 by use of chromosome-mediated gene transfer

We used somatic-cell hybrids, containing as their only human genetic contribution part or all of chromosome 17, as donors for chromosome-mediated gene transfer. A total of 54 independent transfectant clones were isolated and analyzed by use of probes or isoenzymes for greater than 20 loci located on chromosome 17. By combining the data from this chromosome-mediated gene transfer transfectant panel, conventional somatic-cell hybrids containing well-defined breaks on chromosome 17, and in situ hybridization, we propose the following order for these loci: pter-(TP53-RNP2-D17S1)-(MYH2-MYH1)-D17Z 1-CRYB1-(ERBA1-GCSF-NGL)-acute promyelocytic leukemia breakpoint-RNU2-HOX2-(NGFR-COLIAI-MPO)-GAA-UM PH-GHC-TK1-GALK-qter. Using chromosome-mediated gene transfer, we have also regionally localized the random probes D17S6 to D17S19 on chromosome 17.

Cloning and sequencing of cDNA encoding human DNA topoisomerase II and localization of the gene to chromosome region 17q21-22

Two overlapping cDNA clones encoding human DNA topoisomerase II were identified by two independent methods. In one, a human cDNA library in phage lambda was screened by hybridization with a mixed oligonucleotide probe encoding a stretch of seven amino acids found in yeast and Drosophila DNA topoisomerase II; in the other, a different human cDNA library in a lambda gt11 expression vector was screened for the expression of antigenic determinants that are recognized by rabbit antibodies specific to human DNA topoisomerase II. The entire coding sequences of the human DNA topoisomerase II gene were determined from these and several additional clones, identified through the use of the cloned human TOP2 gene sequences as probes. Hybridization between the cloned sequences and mRNA and genomic DNA indicates that the human enzyme is encoded by a single-copy gene. The location of the gene was mapped to chromosome 17q21-22 by in situ hybridization of a cloned fragment to metaphase chromosomes and by hybridization analysis with a panel of mouse-human hybrid cell lines, each retaining a subset of human chromosomes.

The mode of action of nerve growth factor in PC12 cells

This review deals with the mechanism of nerve growth factor action. In view of the many and diversified effects of this growth factor, and since it could utilize different mechanism(s) in distinct types of cells, we have confined our analysis to the best characterized and more extensively studied target, the clonal cell line PC12. When exposed to NGF in vitro, these neoplastic cells recapitulate the last major steps of neuronal differentiation, i.e., the commitment to become a neuron and the acquisition of the neuronal phenotype. This is characterized by electrically excitable neurites, a display of a highly organized cytoskeleton, and the specific chemical and molecular neuronal properties. These effects are elicited upon the interaction of NGF with a receptor whose gene has been cloned and whose kinetic properties are now relatively well characterized. It is not yet clear, on the contrary, if and which of the several potential second messengers (cAMP, Ca, or phosphoinositides) that undergo marked fluctuations following NGF binding, transduce and amplify the NGF message. Among both the early and late effects of NGF is the modulation of expression of several genes. Some of the products of these genes are mainly restricted to nerve cells and others appear to play a crucial role in regulating the proper assembly of cytoskeletal elements. It is hypothesized that this complex array of chemical, molecular, and ultrastructural changes is triggered by NGF, not through activation of a single pathway, but more likely via combinatorial processes whereby several intracellular signals interplay before the irreversible commitment of becoming a neuron is undertaken.

The cytogenetics of childhood leukemia: clinical and biologic implications

Cytogenetic studies have revealed a broad spectrum of abnormalities in the chromosomal make-up of human leukemic cells. These abnormalities are acquired during the process of malignant transformation within the neoplastic clone and reflect the genetic lesions and ablations that have occurred. Because cytogenetic abnormalities are tightly linked to the molecular events that lead to leukemogenesis, it is not surprising that these features correlate with immunophenotypic and morphologic features of the leukemic cells, as well as with the clinical characteristics of children at diagnosis and their responsiveness to therapy. Molecular analysis of the disordered structure or disrupted regulation of genes located at critical chromosomal breakpoints in leukemic cells should continue to provide important insight into normal and aberrant hematopoietic cell function.

Induction of nerve growth factor receptors on cultured human melanocytes

Normal differentiation and malignant transformation of human melanocytes involve a complex series of interactions during which both genetic and environmental factors play roles. At present, the regulation of these processes is poorly understood. We have induced the expression of nerve growth factor (NGF) receptors on cultured human melanocytes with phorbol 12-tetradecanoate 13-acetate and have correlated this event with the appearance of a more differentiated, dendritic morphology. Criteria for NGF receptor expression included protein accumulation and cell-surface immunofluorescent staining with a monoclonal antibody directed against the human receptor and induction of the messenger RNA species as determined by blot-hybridization studies. The presence of the receptor could also be induced by UV irradiation or growth factor deprivation. The NGF receptor is inducible in cultured human melanocytes, and we suggest that NGF may modulate the behavior of this neural crest-derived cell in the skin.

Human gene coding for granulocyte-colony stimulating factor is assigned to the q21-q22 region of chromosome 17

Granulocyte-colony stimulating factor (G-CSF) is a member of colony stimulating factors which regulate the proliferation and differentiation of hematopoietic progenitor cells. A full-length cDNA clone coding human G-CSF was used as a hybridization probe to detect homologous sequence in human-mouse somatic cell hybrids, flow-sorted human chromosomes, and in situ human metaphase chromosomes. The results indicate that the gene encoding human G-CSF is on the q21-q22 region of chromosome 17, which is involved in translocation of t(15;17) (q23;21) in human acute promyelocytic leukemia.

The gene encoding human vimentin is located on the short arm of chromosome 10

The gene for vimentin, an intermediate-filament protein, is growth regulated. We used Southern blot analysis and in situ chromosome hybridization to determine the location of the human vimentin gene. Our results show that there is only one copy of the vimentin gene and that it is located on the short arm of chromosome 10 (10pter-10q23) close to the interleukin-2 receptor gene, which is also growth regulated. In situ hybridization studies suggest that the most likely location of the vimentin gene is 10p13. Sequence similarities and homologies of human vimentin to other genes are presented.

Human homeo box-containing genes located at chromosome regions 2q31----2q37 and 12q12----12q13

Four human homeo box-containing cDNAs isolated from mRNA of an SV40-transformed human fibroblast cell line have been regionally localized on the human gene map. One cDNA clone, c10, was found to be nearly identical to the previously mapped Hox-2.1 gene at 17q21. A second cDNA clone, c1, which is 87% homologous to Hox-2.2 at the nucleotide level but is distinct from Hox-2.1 and Hox-2.2, also maps to this region of human chromosome 17 and is probably another member of the Hox-2 cluster of homeo box-containing genes. The third cDNA clone, c8, in which the homeo box is approximately 84% homologous to the mouse Hox-1.1 homeo box region on mouse chromosome 6, maps to chromosome region 12q12----12q13, a region that is involved in chromosome abnormalities in human seminomas and teratomas. The fourth cDNA clone, c13, whose homeo box is approximately 73% homologous to the Hox-2.2 homeo box sequence, is located at chromosome region 2q31----q37. The human homeo box-containing cluster of genes at chromosome region 17q21 is the human cognate of the mouse homeo box-containing gene cluster on mouse chromosome 11. Other mouse homeo box-containing genes of the Antennapedia class (class I) map to mouse chromosomes 6 (Hox-1, proximal to the IgK locus) and 15 (Hox-3). A mouse gene, En-1, with an engrailed-like homeo box (class II) and flanking region maps to mouse chromosome 1 (near the dominant hemimelia gene). Neither of the class I homeo box-containing genes--c8 and c13--maps to a region of obvious homology to chromosomal positions of the presently known mouse homeo box-containing genes.

Developmentally regulated expression of the nerve growth factor receptor gene in the periphery and brain

Nerve growth factor (NGF) regulates development and maintenance of function of peripheral sympathetic and sensory neurons. A potential role for the trophic factor in brain has been detected only recently. The ability of a cell to respond to NGF is due, in part, to expression of specific receptors on the cell surface. To study tissue-specific expression of the NGF receptor gene, we have used sensitive cRNA probes for detection of NGF receptor mRNA. Our studies indicate that the receptor gene is selectively and specifically expressed in sympathetic (superior cervical) and sensory (dorsal root) ganglia in the periphery, and by the septum-basal forebrain centrally, in the neonatal rat in vivo. Moreover, examination of tissues from neonatal and adult rats reveals a marked reduction in steady-state NGF receptor mRNA levels in sensory ganglia. In contrast, a 2- to 4-fold increase was observed in the basal forebrain and in the sympathetic ganglia over the same time period. Our observations suggest that NGF receptor mRNA expression is developmentally regulated in specific areas of the nervous system in a differential fashion.

Papillomavirus sequences integrate near cellular oncogenes in some cervical carcinomas

The chromosomal locations of cellular sequences flanking integrated papillomavirus DNA in four cervical carcinoma cell lines and a primary cervical carcinoma have been determined. The two human papillomavirus (HPV) 16 flanking sequences derived from the tumor were localized to chromosome regions 20pter----20q13 and 3p25----3qter, regions that also contain the protooncogenes c-src-1 and c-raf-1, respectively. The HPV 16 integration site in the SiHa cervical carcinoma-derived cell line is in chromosome region 13q14----13q32. The HPV 18 integration site in SW756 cervical carcinoma cells is in chromosome 12 but is not closely linked to the Ki-ras2 gene. Finally, in two cervical carcinoma cell lines, HeLa and C4-I, HPV 18 DNA is integrated in chromosome 8, 5' of the c-myc gene. The HeLa HPV 18 integration site is within 40 kilobases 5' of the c-myc gene, inside the HL60 amplification unit surrounding and including the c-myc gene. Additionally, steady-state levels of c-myc mRNA are elevated in HeLa and C4-I cells relative to other cervical carcinoma cell lines. Thus, in at least some genital tumors, cis-activation of cellular oncogenes by HPV may be involved in malignant transformation of cervical cells.

The human c-ros gene (ROS) is located at chromosome region 6q16----6q22

The human homolog, c-ros, of the transforming gene, v-ros, of the avian sarcoma virus, UR2, has been isolated from a human genomic library. A single-copy fragment from the human c-ros genomic clone has been used to map the human c-ros homolog (ROS) to human chromosome region 6q16----6q22 by somatic cell hybrid analysis and chromosomal in situ hybridization. Thus, the c-ros gene joins the c-myb oncogene, which is distal to the c-ros gene on the long arm of human chromosome 6, as a candidate for involvement in chromosome 6q deletions and rearrangements seen in various malignancies.