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A Deisseroth

Publications and source records attributed to A Deisseroth.

89 records · Page 5Linked to original sources
PubMed1976

Extinction of globin gene expression in human fibroblast x mouse erythroleukemia cell hybrids.

We have chosen human fibroblast x mouse erythroleukemia hybrid cells as a model system to examine regulation of unique genes. The globin genes were studied as a marker of erythroid differentiation. Three separate hybrid cell lines were incubated in 2% dimethylsulfoxide, an agent which induces erythroid differentiation of the parental erythroleukemia cells. Neither human nor mouse globin mRNA sequences could be detected by a sensitive molecular hybridization assay which utilized globin complementary D N A. However, td n a from one of the cell lines was shown to contain both the mouse and humand globin genes. Thus, loss of the genes by chromosomal segregation did not account for their failure to be expressed. Cocultivation of the mouse erythroleukemia cells with excess human fibroblasts did not prevent erythroid differentiation of the erythroleukemia cells in the presence of dimethylsulfoxide. Similarly globin gene expression was preserved in tetraploid cells generated by fusion of two erythroleukemia lines. Thus, extinction of globin geneated by fusion of two erythroleukemia lines. Thus, extinction of blobin gene expression in the human fibroblast x erythroleukemia hybrids occurred at the level of mRNA production and appeared to be due to the presence of the fibroblast genome within the hybrial cell.

Animals↗
PubMed1976

Study of markers of human erythroid differentiation in hybrid cells.

Somatic cell hybrids exhibiting co-expression of the globin genes of two species were generated by fusion of mouse erythroleukemia cells with Chinese hamster or human marrow erythroid cells. In contrast, extinction of the mouse globin genes occurred in hybrids formed between the erythroleukemia cells and human fibroblasts. Direct detection of the human globin genes in human X mouse fibroblast hybrids was achieved by annealing of DNA from these cells to human globin complementary DNA. This method was developed to permit the chromosomal assignment of the human globin genes.

Animals↗
PubMed1975

Hemoglobin synthesis in somatic cell hybrids: globin gene expression in hybrids between mouse erythroleukemia and human marrow cells or fibroblasts.

Somatic cell hybrids were generated by fusion of mouse erythroleukemia cells either to mouse L cells (B82), human fibroblasts (W1-18 VA2), or human marrow fractions enriched in erythroblasts. The hybrid cells were examined for globin gene expression by benzidine staining to detect cytoplasmic hemoglobin, and by molecular hybridization of cellular RNA to globin complementary DNA (cDNA) to detect globin messenger RNA (MRNA). The fibroblast (human or mouse) times erythroleukemia cell hybrids grown in monolayer retained most of the chromosomes of each parent. Neither cytoplasmic hemoglobin nor globin mRNA was detected in dimethylsulfoxide-treated fibroblast times erythroleukemia hybrid cells, indicating extinction of hemoglobin synthesis prior to the formation of cytoplasmic mRNA. The human marrow times mouse erythroleukemia hybrid cells grown in suspension culture contained only a few human chromosomes and exhibited low levels of hemoglobin synthesis which were amplified by 2% dimethylsulfoxide. Mouse (but not human) globin mRNA was demonstrated in these hybrid cells. The results suggest that somatic cell hybrids may be useful in searching for genetic factors which regulate activity of the globin genes.

Bone Marrow Cells↗
PubMed1975

Hemoglobin synthesis in somatic cell hybrids: coexpression of mouse with human or chinese hamster globin genes in interspecific somatic cell hybrids of mouse erythroleukemia cells.

Somatic cell hybrids were derived by fusion of mouse erythroleukemia cells with fractionated human marrow enriched in erythroblasts, or with chinese hamster fetal liver erythroid cells. Such interspecific hybrid cells, when isolated in suspension culture, had retained nearly all the mouse chromosomes and had lost most of the human or chinese hamster chromosomes. However, two such hybrids (one human, the other hamster) studied 4-6 weeks after fusion, were found to contain several non-mouse chromosomes. RNA extracted from the human marrow x erythroleukemia hybrid annealed equally to both human and mouse globin complementary DNA, indicating that coexpression of the globin genes of each species had occurred in the hybrid cells. Mouse and human mRNA were found to accumulate only after incubation of the cells in 2% dimethylsulfoxide. The chinese hamster x erythroleukemia hybrid appeared to contain a double complement of mouse chromosomes in addition to several chinese hamster chromosomes. After 7 days of incubation in 2% dimethylsulfoxide, [3H]leucine was incorporated into chinese hamster beta-globin and the mouse globin chains. Thus, globin genes from differentiated cells, when introduced into spontaneously proliferating erythroleukemia cells, may be expressed after exposure of the resulting hybrid cells to an agent capable of inducing hemoglobin synthesis in the erythroleukemia cell.

Animals↗
PubMed1972

Alteration of the cytotoxic action of sensitized lymphocytes by cholinergic agents and activators of adenylate cyclase.

The cytotoxic action of lymphocytes upon cells bearing alloantigens to which they are sensitized is inhibited by agents that elevate intracellular amounts of 3':5'-cyclic AMP: prostaglandin E(1), cholera toxin, and theophylline. Cholinergic agents, added in the range of 1 to 100 pM, enhance cytotoxicity, an effect that is blocked by atropine. Because cholinergic agents elevate cyclic GMP in other in vitro systems, these findings suggest that the cytotoxic process effected by sensitized lymphocytes is a secretory phenomenon modulated by cyclic AMP and cyclic GMP.

Acetylcholine↗