[Gene expression in normal and virally transformed erythroid cells and the effect of stress factors]. / Ekspressiia genov v normal'nykh i transformirovannykh virusom éritroidnykh kletkakh i deistvie faktorov stressa.

The globin gene expression in normal and Rauscher virus-transformed murine erythroid cells and the effect of heatshock and cycloheximide (CHI) were investigated. The hybridization analysis of RNA transcripts synthesized using erythroid cell chromatin as a template with globin cDNA demonstrated the disturbance of globin gene transcription in transformed erythroblasts. Using the Northern hybridization analysis of poly(A) +RNA with pCR1 beta MG9 as a probe, the presence of a rather broad RNA set (from approximately 1500 to 450 nucleotides) in these cells was discovered, while hemoglobin was not synthesized. This indicated that the processing of globin mRNA was probably also disturbed. As a result of heatshock, the RNA set approached that in normal erythroid cells (500-650 nucleotides), and the proteins corresponding to globins were synthesized. The stable appearance of low molecular weight proteins and the irregular synthesis of HSP-90 and HSP-70 in response to heat shock were the characteristic features of transformed erythroblasts. After CHI treatment, the content of globin sequences in RNA of transformed erythroblasts increased and beta-globin protein chains appeared.

[Heat-shock gene expression in murine erythroid cells]. / Ekspressiia genov teplovogo shoka v éritroidnykh kletkakh myshi.

The effect of the heat-shock stress factor on protein synthesis in Rauscher virus-transformed murine erythroblasts with blocked hemoglobin synthesis was studied. The most pronounced heat-shock protein (HSP) synthesis was observed at 43 and 45 degrees C. Under conditions of heat shock the cells examined demonstrated enhanced (or new) synthesis of HSP with relative mol. mass of approximately 70-80 kD, approximately 50 kD and approximately 15-25 kD. No stable induction of 90 kD heat-shock protein was observed. The characteristic feature of transformed erythroblasts was a sufficiently stable appearance of low-molecular HSP with mol. mass from 14 kD to 25 kD, among which there were proteins with relative mol. mass corresponding to that of globin chains.

[Effect of cycloheximide on transcription in eukaryotic cells]. / Vliianie tsiklogeksimida na transkriptsiiu v éukarioticheskikh kletkakh.

The effects of the translation inhibitor cycloheximide on transcription in Rauscher virus transformed mouse erythroblasts and in barley rootlets were studied. In transformed erythroblasts, the globin gene transcription appeared to be blocked. Consecutive treatment of cells with sublethal doses of cycloheximide (7 micrograms/ml) and actinomycin D resulted in the induction of synthesis of the protein fraction corresponding to beta-globin chains. An exposure of barley rootlets to cycloheximide caused changes in total RNA synthesis.

[Effect of non-histone chromatin proteins on the transcription of globin genes]. / Vliianie negistonovykh belkov khromatina na transkriptsiiu globinovykh genov.

Globin gene transcription was studied in vitro using chromatin of normal and Rauscher virus-transformed erythroid cells. For this purpose the reconstituted chromatin was obtained and used as a template for RNA synthesis. The RNA-transcript was then analysed for the presence of globin mRNA sequences. When chromatin was reconstituted using DNA from Rauscher-transformed erythroblasts and reticulocyte nonhistone proteins they enhanced transcription. Most of the globin gene activation was due to the nonhistone protein fraction eluted from hydroxylapatite in 0.05 M Na-phosphate and the RNA-transcript in this case contained the largest quantity of globin sequences.

[Transcription of globin gene in erythroid cells transformed by Rauscher virus]. / Transkriptsiia globinovykh genov v éritroidnykh kletkakh, transformirovannykh virusom Raushera.

The synthesis of globin mRNA in cultured murine erythroleukemic cells transformed by the Rauscher leukemia virus and in the spleen of mice with Rauscher erythroleukemia was studied. The content of globin RNA sequence was estimated by cDNA hybridization with increasing amounts of cytoplasmic and poly (A)-containing RNA Globin RNA was found in the spleen of mice with Rauscher erythroleukemia, its content in cytoplasmic RNA and poly (A)-containing RNA being 0.02% and 0.4%, respectively. By contrast, no globin RNA sequences were found in transformed cultured murine erythroleukemic cells, which can be a cause of altered hemoglobin synthesis in these cells.

[Genetic diversity of informational RNA in rat tissues]. / Geneticheskoe raznoobrazie informatsionnykh RNK v tkaniakh krysy.

The complexity of rat brain and liver cytoplasmic polyadenylated mRNA has been measured by analysis of the kinetics of hybridization with complementary DNA. For this purpose special computer program was applied. The classes of mRNA and the number of mRNA types in each class in these tissues were defined. The base sequence complexity of rat brain mRNA seems to be higher than that of liver. A comparison of the results with the literary data showed that the method of hybridization kinetics does not yield only possible results.