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U Grundmann

Publications and source records attributed to U Grundmann.

63 records · Page 4Linked to original sources
PubMed1979

Protein coding sequences in newly synthesized nuclear RNA from chicken immature red blood cells.

The contents of globin gene transcripts and other protein coding agene transcript (preferentially expressed in liver) within nuclear RNA from chicken immature red blood cells were analyzed by the method of cDNA hybridization. A comparison of the hybridization values obtained from steady state nuclear RNA and pulse labeled newly synthesized nuclear RNA demonstrated, that (a) there is a vast excess of globin gene transcripts over other individual protein coding transcripts and (b) the ratio of globin gene transcripts to the amount of other protein gene transcripts is nearly the same within both RNA species. We conclude, that in chicken immature red blood cells the globin genes are transcribed either at a much higher rate than other protein coding genes or that most of the transcription products of other genes transcribed at higher rates must be degraded during or very shortly after transcription. Moreover, an accumulation of both types of transcripts was observed, as the contents of these RNA molecules was higher within steady state nuclear RNA than within the newly synthesized RNA.

Animals↗
PubMed1979

Inserts within the mRNA sequence on the 15 S globin mRNA precursor from chicken.

[3H]Uridine pulse-labelled nuclear RNA of chicken immature red blood cells contains two RNA species with globin coding sequences sedimenting at 9 S and 15 S, the latter representing most probably the precursor to 9 S globin mRNA. Whether the globin mRNA sequence on the 15 S precursor is interrupted by interspersed sequences was investigated by hybridization of labelled nuclear 15 S RNA with an excess of unlabelled globin complementary DNA. After degradation of nonhybridized RNA by RNAase A the enzyme was removed by proteinase K and a subsequent phenol extraction. The complementary DNA hybrids were melted and the complementary DNA degraded by DNAase I. For the separation of complementary DNA protected RNA polyacrylamide gel electrophoresis in formamide was used. Three RNA fragments with approximately 320, 200 and 120 nucleotides were found in the case of the 15 S RNA, whereas only one 650-700 nucleotide fragment was detected when the same procedure was carried out with nuclear 9 S RNA. This means, that the chicken 15 S globin mRNA precursor contains at least two inserts within the mRNA sequence, which originate presumably by transcription of a gene with intervening sequences.

Animals↗
PubMed1978

The putative 15 S precursor of globin mRNA contains a poly (A) sequence.

[3H] Uridine or [3H] adenosine pulse-labelled nuclear RNA was isolated from chicken immature red blood cells and separated on denaturing formamide sucrose gradients. RNA of each gradient fraction was hybridized with unlabelled globin DNA complementary to mRNA (cDNA) and subsequently digested by RNAase A and RNAase T1. The experiments revealed two RNA species with globin coding sequences sedimenting 9 S and approx. 15 S, the latter probably representing a precursor of 9 S globin mRNA. A poly (A) sequence was demonstrated in this RNA by two different approaches. Nuclear RNA pulse-labelled with [3H] uridine was fractionated by chromatography on poly (U)-Sepharose. Part of the 15 S precursor was found in the poly(A)-containing RNA. In the second approach 15 S RNA pulse-labelled with [3H]adenosine was hybridized with globin cDNA, incubated with RNAase A and RNAase T1 and subjected to chromatography on hydroxyapatite. The hybrids were isolated and after separation of the strands degraded with DNAase I, RNAase A and RNAase T1. By this procedure poly(A) sequences of approximately 100 nucleotides could be isolated from the 15 S RNA with globin coding sequences. The poly(A) sequence was completely degraded by RNAase T2.

Animals↗
PubMed1977

Nuclear steady-state RNA from chicken immature red blood cells. Distribution of globin-coding and poly (A) sequences.

Nuclear steady-state RNA and polysomal RNA of chicken immature red blood cells were isolated and separated on formamide sucrose gradients. For comparison the distribution of 9 S globin mRNA was investigated by gradient centrifugation of 125I-labelled mRNA. The material was either pooled into two fractions (less than 20 S; greater than 20 S) and translated in an Ehrlich ascites cell-free system or each gradient fraction was analyzed by hybridization with [3H]-poly (U) or [3H]-labelled DNA complementary to purified 9 S globin mRNA (globin cDNA). In neither case could evidence be obtained for the existence of a high molecular weight RNA as a probable globin mRNA precursor. Further analysis was performed by electrophoresis of RNA on exponential polyacrylamide gels in formamide and subsequent hybridization with cDNA. The results are consistent with those of gradient centrifugation and demonstrate that the distribution of globin-coding sequences in nuclear steady state RNA corresponds to that of cytoplasmic 9 S globin mRNA.

Animals↗
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Germany↗
PubMedDate not supplied

[Size comparison of poly (A)-RNA from polysomes and from nuclei of the yeast Saccharomyces cerevisiae (author's transl)].

The size of poly (A)-RNA from polysomes and cell nuclei of the yeast Saccharomyces cerevisiae was investigated. Pulslabelled cells ([14C] adenin) were cracked by the French press; polysomes and nuclei were separately isolated and the RNA was finally extracted with phenol. The separation of poly (A)-containing and poly (A)-lacking fractions was achieved by oligo (dT) cellulose. These fractions were characterized by sedimentation analysis. The main portion of polysomal poly (A)-RNA sedimented with a rate of 8 to 14S, whereas the poly (A)-RNA of nuclei exhibited a sedimentation rate of 12 to 17S. Thus nuclear poly (A)-RNA is about 20-30% larger than polysomal poly (A)-RNA.

Cell Nucleus↗