RESUMEN
Mitotic CHO cells and mouse testicular cells were fused with polyethylene glycol. Several types of prematurely condensed chromosomes were observed. From chromosome morphology it was possible to determine that most of the PCC represented mouse cells. Labeling of either the CHO cells in vitro or the testicular cells in vivo with 3H-TdR prior to fusion also demonstrated that the PCC were derived from the mouse cells. In some PCC, 20 chromosomes could be counted, the haploid number for mouse. It is assumed that these PCC were induced in mouse spermatid nuclei.
Asunto(s)
Cromosomas/ultraestructura , Testículo/ultraestructura , Animales , Fusión Celular , Línea Celular , Cricetinae , Cricetulus , Femenino , Haplorrinos , Masculino , Ratones , Mitosis , Ovario , Timidina/metabolismo , TritioRESUMEN
Using the silver staining technique, in somatic and meiotic chromosomes of the Armenian hamster (Cricetulus migratorius), it is possible to stain synaptonemal complexes (SCs) and the nucleolus organizer regions (NORs) in early spermatocytes. There are five pairs of autosomes (Nos. 2, 4, 6, 7, and 8) which have terminally located NORs. Synaptonemal complexes and accessory structures present in the sex chromosomes within the sex vesicle can be easily observed using light microscopy.
Asunto(s)
Cricetinae/genética , Cricetulus/genética , Región Organizadora del Nucléolo/ultraestructura , Espermatocitos/ultraestructura , Espermatozoides/ultraestructura , Animales , Cromosomas/ultraestructura , Masculino , Meiosis , Metafase , Plata , Coloración y EtiquetadoRESUMEN
We analyzed the karyotypes of nine established human malignant melanoma cell lines derived from two female and six male patients. Each of the cell lines had an aneuploid stemline chromosome number. Analysis of G-banded chromosomes identified a number of altered (marker) chromosomes in these cell lines; in all the lines, chromosome 6 was found to be involved in the marker chromosomes. A review of the literature and these cases showed that of 47 cell lines or primary melanoma cells karyotyped, 38 (80.8%) had a marker involving the 6. We believe that the genetic factor determining melanoma initiation is located in the distal segment of 6q. Deletion of this segment or the entire 6q is responsible for the cell's (melanoblast or melanocyte) becoming malignant. The proximal segment of 6q and 6p can be involved in marker formation.
Asunto(s)
Deleción Cromosómica , Cromosomas Humanos 6-12 y X/ultraestructura , Melanoma/genética , Línea Celular , Bandeo Cromosómico , Femenino , Humanos , Cariotipificación , Masculino , Translocación GenéticaRESUMEN
We have previously demonstrated that translocations of V(H) genes from chromosome 14 to chromosome 8 and of the c-myc oncogene from chromosome 8 to chromosome 14 occur in Burkitt lymphomas with the t(8;14) chromosome translocation. An association of the c-myc gene with the C(mu) immunoglobulin gene has been observed in some but not all Burkitt lymphomas studied previously. In the present study, we have investigated the organization of the human heavy chain locus and of the c-myc gene in the P3HR-1 Burkitt lymphoma cell line. Becuase mouse/P3HR-1 somatic cell hybrids that retain only the 14q+ chromosome and no other human chromosome contain the human C(mu) and C(gamma) genes but not V(H) genes, we have concluded that the breakpoint on chromosome 14 in P3HR-1 cells is distal to C(mu) and between C(mu) and V(H). Thus, the breakpoint of human chromosome 14 differs in different Burkitt lymphoma cell lines. We also found that the human c-myc oncogene translocated to chromosome 14 in the P3HR-1 cell line is not recombined with the C(mu) gene. The breakpoint on human chromosome 8 may therefore also differ in different Burkitt lymphoma cell lines, because we have observed DNA rearrangement of the c-myc gene with the C(mu) gene in only some of the Burkitt lymphoma cell lines studied elsewhere. Interestingly, high levels of transcripts of the c-myc oncogene were observed in Burkitt lymphomas with translocated c-myc oncogenes both rearranged and unrearranged. Therefore, the translocation of a c-myc oncogene to the heavy chain locus on human chromosome 14 is apparently sufficient for its transcriptional activation and may be an essential step in the pathway leading to neoplasia.
Asunto(s)
Linfoma de Burkitt/genética , Cromosomas Humanos 13-15 , Cromosomas Humanos 6-12 y X , Regulación de la Expresión Génica , Oncogenes , Ligamiento Genético , Humanos , Cadenas Pesadas de Inmunoglobulina/genética , Transcripción Genética , Translocación GenéticaRESUMEN
The NIGMS Human Genetic Mutant Cell Repository is currently distributing two well-characterized human/rodent somatic cell hybrid mapping panels. Mapping Panel 1 consists of DNA isolated from 18 hybrid cell cultures retaining from 1 to 19 human chromosomes. Mapping Panel 2 contains DNA from hybrids retaining 1 or 2 human chromosomes. All but 2 of the hybrids retain a single intact human chromosome. Mapping Panel 2 is also available as cell cultures. These resources should prove valuable to the Human Genome Project initiative. This article describes the sources of the hybrid cell cultures and the procedures utilized to prepare and characterize the panels.
Asunto(s)
Mapeo Cromosómico , Cromosomas Humanos , Células Híbridas , Animales , Bases de Datos Factuales , Humanos , Masculino , Ratones , National Institutes of Health (U.S.) , Estados UnidosRESUMEN
The NIGMS Human Genetic Mutant Cell Repository collects and distributes well-characterized human/rodent somatic cell hybrid regional mapping panels for human chromosomes 3, 4, 5, 11, 15, 17, 18, and X. Each regional mapping panel consists of 4 to 11 hybrids that divide the chromosome into 5 to 11 intervals. These panels have been extensively characterized by the submitters and the NIGMS Repository.