Search PubMed⌕ Search

Biomedical subjects

N Affara

Publications and source records attributed to N Affara.

25 records · Page 2Linked to original sources
PubMed1975

Control of transcription of the globin gene.

This report provides a more rigorous proof of previous findings that the RNA transcribed in vitro from the chromatins of different organs shows different sequence specificities. Here the particular case of the globin gene is considered for a comparison of embryonic mouse liver chromatin and mouse brain chromatin using the reverse transcriptase cDNA copy of globin 9S m RNA as a definitive probe. It can be shown that globin sequences are transcribed in vitro from embryonic liver chromatin and not brain chromatin. This specificity in liver chromatin can be reconstituted after dissociation of the structural elements of the chromatin. It can be shown that the non-histone protein fraction of liver chromatin can confer specificity for the transcription of globin sequences from brain chromatin which otherwise lacks this ability. Preliminary results are described with the Friend cell system, in which haemoglobin synthesis can be induced in vitro in the presence of dimethylsulphoxide.

Animals↗
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.

Animals↗
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.

Animals↗