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M J Getz

Publications and source records attributed to M J Getz.

48 records · Page 3Linked to original sources
PubMed1978

Equivalent expression of endogenous murine leukemia virus-related genes in C3H/10T1/2 cells and chemically transformed derivative cells.

The possibility that chemical carcinogens may induce enhanced expression of endogenous C-type RNA tumor virus genes in the absence of intact virus particle production has been partially tested in a model system. Thie was accomplished by measuring the abundance and diversity of murine leukemia virus-related RNA sequences associated with the polyribosome fraction of nontransformed C3H/10T1/2 clone 8 cells and a 3-methylcholanthrene-transformed derivative clone. Although both clones are virus nonproducers, they were found to contain significant amounts of polyadenylate-containing murine leukemia virus-related RNA sequences; however, both the types and quantities of such sequences appear indistinguishable in both clones. These results suggest that expression of the corresponding gene sequences into RNA is not related to the maintenance of the transformed state in these chemically transformed cells.

Base Sequence↗
PubMed1976

Effect of cell proliferation on levels and diversity of poly(A)-containing mRNA.

The relationship between cell proliferation and the amount and diversity of polyribosome-associated poly(A)-containing messenger RNA [poly(A)+mRNA]has been investigated using a cloned AKR-mouse embryo cell culture system. The following results were obtained. First, an early response to the stimulation of proliferation of AKR-2B cells in culture is a rapid increase in the rate of accumulation of polyribosomal poly(A)+ mRNA. This results in a large increase in the total poly(A)+ mRNA content of rapidly proliferating cells compared to that found in resting cells. Second, the total amount of unique DNA sequence contributing to the poly(A)+ mRNA populations of both growing and resting cells is not detectably different. This corresponds to 9000-11,000 diverse gene equivalents of DNA and represents the transcription of 0.8-0.9% of the haploid mouse genome. Third, most of the increased poly(A)+ mRNA content of growing cells (greater than 90%) reflects an increased rate of production of polysomal mRNA species which are also found in resting cells. Fourth, growing cells appear to contain some species of poly(A)+ mRNA which are either absent or present in very low concentrations in non-growing cells. Within the limits of detection, however, all species of poly(A)+ mRNA present in non-growing cells are also present in growing cells.

Cell Division↗
PubMed1975

A kinetic estimation of base sequence complexity of nuclear poly(A)-containing RNA in mouse Friend cells.

Complementary DNA (cDNA) has been transcribed by viral reverse transcriptase from poly(A)-containing nuclear RNA prepared from growing mouse Friend cells (clone M2). Annealing experiments with this cDNA have demonstrated that a large proportion of the poly(A) tracts in M2 cell nuclear RNA are adjacent to RNA sequences which are transcribed from nonrepetitive DNA in the mouse genome. The kinetics of hybridization of cDNA to template RNA indicate that nuclear poly(A)-containing RNA consists of at least two abundance classes, the more complex of which is transcribed from approximately 3 percent of the genome. Thus there are at least 5 times more unique DNA sequences represented in nuclear polyadenylated RNA than in polysomal polyadenylated RNA. Moreover, there is evidence for posttranscriptional mechanisms which alter the relative concentrations of some (at least) gene transcripts between nucleus and cytoplasm.

Adenine Nucleotides↗
PubMed1973

125 I-labeled DNA-RNA hybrids in cytological preparations.

RNA complementary to bulk humanplacental DNA was synthesized in vitro both in the presence and absence of (3)H-labeled ribonucleotides. The (3)H-labeled RNA was used directly for hybridization to the DNA of human metaphase chromosomes, whereas the unlabeled complementary RNA was labeled chemically with (125)I before hybridization. A comparison of autoradiographs produced by either isotope revealed no qualitative differences in the chromosomal annealing sites of the same population of RNA molecules. Since (125)I-labeled nucleic acids give similar, if not identical, results as do (3)H-labeled nucleic acids in in situ hybridization experiments, their use should make possible the localization of genetic elements for which tritium labeling methods are either inadequate or not possible.

Autoradiography↗