The linkage of genes for the human interferon-induced antiviral protein and indophenol oxidase-B traits to chromosome G-21.

13 independent mouse-human somatic cell hybrid clones derived from beta-propiolactone-inactivated Sendai stimulated cell fusion of human cells with mouse cells were tested for their sensitivities to human and mouse interferon. All of them were protected by mouse interferon and only six of the clones were protected by both human and mouse interferon. Only the six that were protected by human interferon were shown to express the human dimeric form of indophenol oxidase. Complete chromosomal analysis of the clones indicated human chromosome G-21 to be the only human chromosome in common for the six clones which had both phenotypes present. Nine subclones were derived from one of the clones expressing both phenotypes. Eight of the nine subclones were shown to retain both phenotypes, whereas one subclone lost both. Chromosomal analysis of the subclones indicated the loss of chromosome G-21 from the subclone which lost both phenotypes. It is apparent from these findings that the gene(s) for indophenol oxidase (IPO-B) and the gene(s) for the antiviral protein are syntenic and that they are linked to human chromosome G-21.

J chain is encoded by a single gene unlinked to other immunoglobulin structural genes.

Immunoglobulin J chain mediates the polymerization of both IgM and IgA immunoglobulins. Its synthesis is closely regulated in B lymphocytes, apparently at the level of RNA transcription. To define the genetic bases of this regulation, we have determined the location and number of J chain genes in the mouse. Analysis of DNA from a group of somatic cell hybrids containing various mouse chromosomes on a constant background of Chinese hamster chromosomes indicated that this gene is located on mouse chromosome 5, unlinked to immunoglobulin heavy and light chain structural genes. Restriction mapping experiments further suggested the existence of a single J chain gene per haploid genome. This result was confirmed by quantitative analyses of band intensities yielded by Southern blots of mouse genomic DNA and J gene-containing plasmid DNA.

Chromosomal location of the structural gene cluster encoding murine immunoglobulin heavy chains.

To determine the chromosomal location of mouse immunoglobulin heavy chain structural genes unambiguously, a panel of somatic cell hybrids was scored for the presence of DNA sequences homologous to gamma 2b-, mu-, and alpha-heavy chain-constant region DNA probe molecules. The hybrids, formed between mouse and hamster cells, contained various combinations of mouse chromosomes plus a full set of hamster chromosomes. Hybrids that retained mouse chromosome 12 reacted with the probes, whereas hybrids that had lost the chromosome, or its distal half, failed to react. These results indicate that structural genes for the gamma 2b-, mu-, and alpha-heavy chain-constant regions map to the distal half of this chromosome.

Chromosomal location of structural genes encoding murine immunoglobulin lambda light chains. Genetics of murine lambda light chains.

To determine the chromosomal localization of murine lambda light (L) chain structural genes, DNA from a panel of 11 mouse x hamster somatic cell hybrids was scored for the presence of sequences homologous to cloned lambda DNA probe molecules. Six of the hybrids had detectable lambda I and lambda II gene sequences. In all six, the full complement of murine sequences was present, and in its germline configuration. The remaining hybrids lacked any detectable murine lambda L chain gene sequences. The only mouse chromosome present in all of the positive hybrids and absent from the negative ones was number 16, allowing the assignment of lambda L chain structural genes to this chromosome. Together with the previous assignments of the kappa L chain genes to chromosome 6 and heavy chain genes to chromosome 12, this finding completes the mapping of Ig structural genes in the mouse at the chromosomal level.

Chromosome assignment of the tumor-specific antigen of a 3-methylcholanthrene-induced mouse sarcoma.

Chemically induced sarcomas of inbred mice express antigens that are distinct and specific for each individual tumor. Chromosome assignment of tumor-specific antigens would help to elucidate the genetic basis of their diversity. Expression of the serologically defined Meth A sarcoma antigen is not suppressed in hybrid cells containing a complete foreign (Chinese hamster) genome. Chromosome and serologic analysis of microcell hybrids between Meth A sarcoma cells and Chinese hamster cells shows a clear correlation of Meth A antigen expression with the presence of the distal region of chromosome 12 (bands F1 and F2). Chromosome 16 may also be implicated. The significance of the close linkage of genes determining Meth A antigen expression with the immunoglobulin heavy chain gene cluster (on chromosome 12) and the lambda light chain genes (on chromosome 16) is discussed.

Multiple human beta interferon genes.

Analysis of human beta interferon (IFN) mRNA preparations obtained from poly(I) . poly (C)-induced human diploid fibroblasts (FS-4) and from several similarly induced human-mouse somatic cell hybrids by electrophoresis through agarose-CH3HgOH tube gels led to the detection of at least five translationally active human IFN-beta mRNA species. The results obtained are consistent with the existence of IFN-beta genes on different human chromosomes. Marked cell-dependent variability in the expression of these IFN mRNA species was observed.

Regional location of T cell receptor gene Ti alpha on human chromosome 14.

The chromosomal location of Ti alpha was determined by hybridization of a radiolabeled cDNA for the alpha chain of human T cell receptor with 12 human X mouse cell hybrid DNAs cleaved with BamHI. Seven hybrids contained human Ti alpha, while the remaining five lacked it. Only human chromosome 14 matched the distribution of human Ti alpha signal across the mapping panel. Hybrids segregating a chromosome 14 translocation were used to demonstrate that Ti alpha is in the region 14pter greater than 14q21. Thus, the alpha and beta chain genes that contribute structural components to the Ti moiety of the human T cell receptor lie on different chromosomes. In humans, the immunoglobulin heavy chain locus and Ti alpha are in different regions of chromosome 14, with Ti alpha more proximal and the immunoglobulin heavy chain locus more distal.

Genetic and biochemical characterization of human lymphocyte cell surface antigens. The A-1A5 and A-3A4 determinants.

The genes that code for the human lymphocyte cell surface determinants defined by monoclonal antibodies A- 1A5 and A- 3A4 have been genetically mapped. All human chromosomes, except Y, were included in a series of human less than mouse lymphocyte hybrid populations that retained expression of lymphocyte-specific surface markers. Expression of the A- 1A5 and A- 3A4 antigens was quantitated by indirect immunofluorescence and fluorescence-activated cell sorter (FACS) analysis. Hybrid populations heterogeneous for antigen expression were sorted to yield antigenically homogeneous subpopulations. Isozyme analysis indicated concordant segregation of the A- 1A5 determinant with chromosome 10, and the A- 3A4 determinant with chromosome 4. In contrast to the unhybridized human parent cell line (MOLT-4), from which A- 1A5 immunoprecipitated two proteins (160,000 and 125,000 Mr), A- 1A5 only immunoprecipitated a single band (125,000 Mr) from an A- 1A5 -expressing human less than mouse hybrid. The genetic disassociation of these two proteins from the A- 1A5 -reactive complex suggests that the appearance of the 160,000 Mr protein requires a gene locus that is unlinked to the locus for the 125,000 Mr protein on chromosome 10. A third component of the A- 1A5 -reactive protein complex (210,000 Mr), which is recognized by the monoclonal antibody TS2/7, was not expressed on the parent MOLT-4 cells, but was weakly expressed on MOLT-4 less than mouse BW5147 hybrids. This allowed preliminary mapping of that determinant to either chromosome 10 or 15. The A- 3A4 antigen (approximately 45,000 Mr) is a novel cell surface structure expressed on all hematopoietic cell lines tested, and represents the first cell surface marker mapped to chromosome 4.

Assignment of the receptor for ecotropic murine leukemia virus to mouse chromosome 5.

The gene for the receptor for ecotropic murine leukemia virus (Rev) has been assigned to mouse chromosome 5. This determination was made possible by an analysis of somatic cell hybrids between mouse and Chinese hamster cells. The parents of these hybrids were A/HeJ or Mus poschiavinus peritoneal exudate cells or BALB/c primary embryo fibroblasts and E36, a Chinese hamster lung fibroblast deficient in hypoxanthine guanine phosphoribosyltransferase. Segregation of mouse chromosomes in these hybrids was analyzed by chromosome banding and isozyme expression. Cells were tested for their ability to absorb and replicate vesicular stomatitis virus (murine leukemia virus [MuLV]) pseudotype particles and ecotropic MuLV as measured by the XC test. The presence of chromosome 5 was essential for receptor expression as determined by three statistical procedures. Segregation of the receptor for ecotropic murine leukemia virus was also followed in two series of subclones. In both, receptor expression was syntenic with phosphoglucomutase-1, an isozyme which has been mapped to mouse chromosome 5.

Murine T cell receptor beta chain is encoded on chromosome 6.

Southern blot analysis of somatic cell hybrid lines indicates that the beta chain of the T cell receptor for antigen maps to chromosome 6 of the mouse. An experiment testing hybridization of the constant region of this gene to DNA from a hybrid cell line containing a translocation of chromosome 6 supports the localization of this gene to the proximal (centromeric) one-third of chromosome 6, in the same general region as the immunoglobulin kappa chain locus. This may be another indication of the shared evolutionary origins of the genes encoding both T and B cell antigen recognition.