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D Conkie

Publications and source records attributed to D Conkie.

16 recordsLinked to original sources
PubMed1987

Changes in minor transcripts from the alpha 1 and beta maj globin and glutathione peroxidase genes during erythropoiesis.

We have analysed the transcriptional regulation of the murine alpha 1 and beta maj globin genes and the glutathione peroxidase (GSHPx) gene, which are all highly expressed during erythropoiesis. The levels of minor RNAs compared to the major message were monitored throughout differentiation within the erythroid lineage. For each gene, upstream transcripts arise from distinct clusters of sites which are regulated differently during differentiation: some occur only during early erythropoiesis, some occur early and persist to the terminal stages, while others accumulate later and roughly in parallel with the main RNA transcript. In addition, opposite strand transcripts from the GSHPx gene were found in increasing amounts during later stages of erythropoiesis. The initiation sites for specific subsets of these minor transcripts lie close to sequences known to be involved in globin gene regulation (i.e. the TATA, CAAT and the CACCCT boxes) or other conserved sequences; others lie close to developmentally regulated DNase I hypersensitive sites around the globin and GSHPx genes.

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PubMed1981

Cell-cycle dependence of induced hemoglobin synthesis in Friend erythroleukemia cells temperature-sensitive for growth.

Friend erythroleukemia cells temperature-sensitive (ts) for growth have been used to study the cell-cycle dependence of erythroid differentiation. ts cells accumulated hemoglobin in response to inducer when replicating optimally at permissive temperatures. However, when arrested in the G1 phase of the cell cycle at a nonpermissive temperature, ts cells did not accumulate hemoglobin or globin mRNA nor did they differentiate terminally. Under these conditions, the viability of ts cells treated with inducer at the nonpermissive temperature remained high (70% of that of cells induced at the permissive temperature) as judged by cloning experiments. Total RNA and protein synthesis of G1 cells treated with inducer was 44-48% of that of randomly proliferating induced cells, in contrast to thymidine incorporation into DNA which decreased to 2% of that of cells replicating at the permissive temperature. Furthermore, G1 ts cells treated with inducer accumulated hemoglobin when released from growth arrest at the permissive temperature in the presence (but not in the absence) of inducer. These results are consistent with a requirement for a cell cycle-dependent event prior to commitment to differentiation.

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PubMed1974

In situ localization of globin messenger RNA formation. I. During mouse fetal liver development.

Globin mRNA levels in 11-15-day mouse fetal liver cells have been estimated by in situ hybridization of a highly labeled DNA copy (cDNA) of adult globin messenger RNAs (mRNAs) (globin cDNA) to fixed preparations of cells. Under the conditions employed, no significant in situ hybridization occurred to lymphoma cells (L 51787), mouse L cells, or hepatocytes; whereas reticulocytes from phenyl hydrazine-treated mice showed extensive in situ hybridization. The proportion of fetal liver cells showing predominantly cytoplasmic in situ hybridization increased from about 30% at the 11th day of development to 80-85% by days 13-15. Unlike more mature cells, proerythroblasts did not show in situ hybridization, except to a slight extent at later stages of development. These studies therefore indicate that globin mRNAs begin to accumulate during or shortly after the proerythroblastbasophilic erythroblast transition. The fact that certain immature erythroid cells from 14-day fetal liver contain substantial amounts of globin mRNAs has been confirmed by comparing the hybridization in solution of globin cDNA to cytoplasmic RNA extracted from total fetal liver cells or from immature erythroid cells obtained by treatment of fetal liver cells with an antiserum raised against erythrocytes.

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PubMed1974

In situ localization of globin messenger RNA formation. II. After treatment of Friend virus-transformed mouse cells with dimethyl sulfoxide.

Globin messenger RNA (mRNA) levels in Friend virus-transformed mouse cells have been estimated by in situ hybridization of DNA copy (cDNA) to fixed preparations of cells and by hybridization of cDNA to extracted cytoplasmic RNA in true solution. The results obtained by both methods agree in showing that a low level of globin mRNA can be detected in untreated Friend cells. The levels of hemoglobin and globin mRNA have also been correlated after treatment of Friend cells with dimethyl sulfoxide (DMSO). The results obtained by both experimental approaches show that there is a minimum period of treatment with DMSO required in order that Friend cells may become hemoglobinized, and that this period coincides with the time when globin mRNA accumulates. Moreover, bromodeoxyuridine prevents both hemoglobin and globin mRNA accumulation.

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