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Biomedical subjects

G Huez

Publications and source records attributed to G Huez.

At least 73 records · Page 4Linked to original sources
PubMed1976

Globin messenger RNA from anaemic rabbit spleen. Size of its polyadenylate segment.

The size of the polyadenylate segment of globin messenger RNA isolated from spleens of anaemic rabbits was estimated by comparison of its electrophoretic migration in polyacrylamide gels to that of synthetic poly(A) segments of known lengths. Conditions of enzymic degradation of mRNA with pancreatic ribonuclease and T1 ribonuclease were carefully established in order to ensure complete degradation of the heteropolymeric part of mRNA without affecting the polyadenylate sequence. The poly (A) segments of spleen globin mRNA were found to be 25-90 nucleotides long whilst those of peripheral blood reticulocytes from the same animals were only 10-30 residues long. Since spleen contains young erythroid cells and since anucleated blood reticulocytes constitute a statistically older population of the same cell line, these results support the idea that the poly(A) segment of mRNA shortens when the message ages.

Anemia↗
PubMed1976

Molecular modifications associated with Aging of globin messenger RNA in vitro.

Using polyacrylamide gel elution-electrophoresis in aqueous medium, highly purified rabbit globin mRNA can be fractionated into several populations of molecules differing by their mean poly(A) content. Both alpha and beta globin mRNA are heterogenous with respect to their electrophoretic mobilities. With the conditions used no separation of alpha and beta globin mRNA occurs during electrophoresis. From the specific radioactivity distribution in the different mRNA fractions one can conclude that the polyadenylate sequence at the 3' end of globin mRNA molecules becomes shorter with aging. This shortening occurs on alpha as well as beta, globin mRNAs and the extent of heterogeneity in poly(A) content is similar for both globin mRNAs. Furthermore, using two different methods of mRNA fractionation (polyacrylamide gel elution-electrophoresis and elution of poly (U)-Sepharose-bound mRNA at increasing temperatures) it is shown that old mRNA molecules differ from relatively young messages in their ability to direct cell-free globin synthesis. Modifications reducing template activity in vitro thus seem to take place during globin mRNA aging.

Aging↗
PubMed1975

Readenylation of polyadenylate-free globin messenger RNA restores its stability in vivo.

Using an ATP:RNA adenyltransferase from Escherichia coli, a polyadenylic sequence was resynthesized onto rabbit globin mRNA from which the poly (A) segment had been previously removed. Conditions for obtaining a homogenous reconstituted globin mRNA preparation containing 30 adenylic residues per message molecule were determined. The reconstituted globin mRNA was microinjected into Xenopus laevis oocytes. Its stability was very similar to that of native mRNA.

Adenine Nucleotides↗
PubMed1975

Absence of polyadenylate segment in globin messenger RNA accelerates its degradation in Xenopus oocytes.

Rabbit globin poly(A)-free and native mRNA preparations were microinjected into Xenopus oocytes. The amount of globin message remaining after incubation of injected oocytes was determined by molecular hybridization with a radioactive complementary DNA probe, synthesized by copying globin mRNA with purified RNA-dependent DNA polymerase (reverse transcriptase) from avian myeloblastosis virus. The results show that 56 hr after injection about 85% of the poly(A)-free mRNA molecules are degraded, while native poly(A)-containing mRNA chains are almost completely preserved during the same period of time.

Animals↗
PubMed1974

Role of the polyadenylate segment in the translation of globin messenger RNA in Xenopus oocytes.

The translations of native messenger RNA for rabbit globin and that of poly(A)-free globin messenger RNA have been compared after injection into Xenopus oocytes. The initial rate of translation of poly(A)-free mRNA is close to that found with intact mRNA. However, at longer incubation periods, the rate of globin synthesis with poly(A)-free mRNA is considerably lower than with native mRNA. Similar differences in the template activity of the two mRNA preparations were found with a cell-free extract of Krebs II ascites tumor. It is concluded that the presence of the 3' poly(A)-rich sequence in mRNA is required to ensure high functional stability.

Adenine Nucleotides↗