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J B Lingrel

Publications and source records attributed to J B Lingrel.

At least 163 records · Page 9Linked to original sources
PubMed1975

Determination of secondary structure in rabbit globin messenger RNA by thermal denaturation.

The secondary structure of highly purified globin messenger RNA has been investigated by alkaline hydrolysis, nuclease digestion, and thermal denaturation. The thermal denaturation properties of globin messenger have been compared to poly(U), poly (A), and a synthetic random sequence RNA copolymer. From these studies it is concluded that globin mRNA contains considerable secondary structure and that the amount of helical structure is greater than that which occurs with a random sequence polyribonucleotide. Globin mRNA contains, by comparison to the secondary structures of native DNA, tRNAs, or 18S rRNA, helices with involve 55-62% of the bases or 58-68% if a correction is made for the 3'-terminal poly(A) segment. The helices of globin mRNA appear to be unique as differences in the NaCl stabilization of this RNA have been noted when compared to other naturally ooccurring and synthetic RNAs. Comparison of the hyperchromicity maxima, obtained at 260 and 280 nm for globin mRNA and 18S rRNA, indicates that the helices of the two RNAs contain similar numbers of G-C base pairs. Differential analysis of NaCl stabilization curves indicate three discrete thermally denaturable helix types in globin mRNA.

Animals↗
PubMed1975

Size of the polyadenylic acid region of newly synthesized globin messenger ribonucleic acid.

The size of the polyadenylic acid region of newly synthesized globin mRNA was determined on mRNA isolated from nucleated erythroid spleen cells of anemic mice. The globin mRNA was purified by a combination of affinity chromatography on oligodeoxythymidylate-cellulose (oligo-(dT)-cellulose) and sucrose density gradient centrifugation. The purified RNA was shown to be globin mRNA by virtue of its ability to direct the synthesis of mouse alpha- and beta-globin chains in a cell-free system and by the presence of two bands migrating identically with authentic mouse alpha- and beta-globin mRNA when subjected to electrophoresis in polyacrylamide gels in the presence of formamide. When labeled for 1 hour with [3H]adenosine, the newly synthesized radioactive mRNA also migrated as two bands in these gels but they moved slower than the main bands suggesting that they have higher molecular weights. The polyadenylic acid region of the mRNA was isolated from the T1 and pancreatic RNase digestion mixture by acrylamide sodium dodecyl sulfate gel electrophoresis. The polyadenylic acid region was found to contain approximately 150 adenylate residues. As it is known that globin mRNA isolated from reticulocytes contains only 40 to 60 residues, it follows that at least 150 adenylic acid residues are added to the globin mRNA soon after its synthesis and that some of these are removed during the subsequent maturation of the erythroid cell.

Adenine Nucleotides↗
PubMed1975

Characterization of globin messenger ribonucleic acids in membrane polysomes of mouse reticulocytes.

Between 20 and 30% of the polysomes in mouse reticulocytes are associated with the cell membrane fraction. These polysomes are not liberated by washing with 0.5 m KCl and are therefore thought to be attached to membranes. They have the same percentage of polyadenylic acid-containing RNA, as determined by oligo(dT)-cellulose affinity chromatography, as cytoplasmic polysomes. Analysis of the RNA by polyacrylamide gel electrophoresis in aqueous solutions shows that at least 95% of the RNA migrates identically with the cytoplasmic polysomal globin mRNAs. Electrophoresis in 99% formamide resolves the membrane mRNAs into two bands which migrate identically with the cytoplasmic alpha- and beta-globin mRNAs. The molar ratio of the alpha- and beta-globin mRNAs, as determined by quantitating the bands on the formamide gels, is similar to that of the cytoplasmic mRNAs. There is also no difference in biological activity between the two messenger preparations. The polyadenylic acid in the membrane mRNAs, isolated after labeling mice in vivo for 20 hours with (32P)orthophosphate, migrates with the three broad size classes previously shown to be present in the cytoplasmic globin mRNAs. The 32P specific activity of the membrane mRNAs and ribosomal RNA fractions after different times of labeling with 32Pi are similar to those from cytoplasmic polysomes. These observations show that the reticulocyte membranes contain approximately 20% of the cellular globin nRNAs, and that these mRNAs are similar to those from cytoplasmic polysomes.

Animals↗
PubMed1972

Initiation factor IF-3-dependent binding of Escherichia coli ribosomes and N-formylmethionine transfer-RNA to rabbit globin messenger.

An initiation complex has been formed in high yields from E. coli ribosomes, 9S messenger RNA for rabbit hemoglobin, and N-formylmethionine-tRNA. Initiation factor IF-3 is required for the binding and puromycin is required for the release of fMet. Valyl-tRNA fails to bind to the second codon, whereas a mixture of 15 aminoacyl-tRNAs promotes incorporation. Together with quantitative data, the findings suggest that IF-3 directs the ribosomes to an AUG codon on one of the two globin messengers, at a site that is different from the normal starting point for globin synthesis.

Acetates↗