Complexity of poly(A<sup>+</sup>) and poly(A<sup>−</sup>) polysomal RNA in mouse liver and cultured mouse fibroblasts

Grady, Leo J.; North, Arlene B.; Campbell, Wayne P.

doi:10.1093/nar/5.3.697

Cited by 48 publications

(13 citation statements)

References 28 publications

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“…The hybridization of polysomal poly(A)+-mRNA to 3 H-labeled single-copy DNA indicates a complexity which is about 75% of that observed for total polysomal RNA (i.e., 1.2 × 107 nucleotides, or 8900 different mRNAs). Thus, the mRNA population in T. cruzi is similar to that of several higher eukaryotic organisms [6,15,16,[26][27][28] in that it exhibits a distinct population of nonadenylated mRNAs (ca. 3000) which is not represented in the poly(A)+-mRNA class.…”

Section: Discussionmentioning

confidence: 99%

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Lanar

Lévy

Manning

1981

Molecular and Biochemical Parasitology

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The content and sequence complexity of the nuclear DNA and messenger RNA for epimastigotes of Trypanosoma cruzi were determined. From analysis of nuclear DNA reassociation studies and microspectrofluorometric measurements of laser induced fluorescence of cellular DNA, T. cruzi is found to be a diploid organism with a nuclear DNA content of 2.5 x 108 nucleotide pairs (2.8 X 10 -~3 g) and a kinetoplast DNA content of 4.9 X 107 nucleotide pairs (5.4 X 10 -t4 g). Reassoeiation kinetics of nuclear DNA of average length 0.4 kb reveals three kinetic components: a moderately repetitive component with a reiteration frequency of 5.1 X 103 present in 9% of the fragments, a lowly repetitive component with a reiteration frequency of 32 present in 51% of the fragments, and a single-copy component present in 23% of the fragments.By saturation hybridization of total polysomal RNA to 3H-labeled single-copy DNA, it was determined that 68% of the single-copy DNA was represented in the epimastigote polysomal RNA. This corresponds to ca. 12 000 different mRNA species. Of these, ca. 9000 are present as poly(A)÷-RNA, while the remaining 3000 appear not to be polyadenylated. Kinetic analysis of the poly(A)+-RNA population indicates it is composed of at least three classes of RNAs of different abundancy levels: two sequences which occur ca. 3000 times per cell, ca. 750 sequences which occur about 20 times per cell, and ca. 15 500 sequences which occur 1-2 times per cell.

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Section: Discussionmentioning

confidence: 99%

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Lanar

Lévy

Manning

1981

Molecular and Biochemical Parasitology

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“…The majority of total mRNA in polysomes from a wide variety of cells appears to contain a 3'-terminal polyadenylic acid [poly(A)] segment (1,3,11,20). Among specific mRNA's, only histone mRNA in mammalian cells appears certain to arrive in the cytoplasm lacking poly(A) (1,3 found in the non-poly(A)+ [poly(A)-] fraction (10,32), whereas other studies suggest almost total overlap in sequence complexity (14) The cytoplasmic half-lives of the poly(A)+ mRNA's were established for each ofthe specific nine mRNA's and ranged from 3 h for the scarcest mRNA to 14 h. At least half of the total newly arrived mRNA molecules turn over considerably faster than 3 h, based on the rising percentage of the total represented by specific mRNA sequences.…”

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confidence: 99%

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

Harpold¹,

Wilson²,

Darnell³

1981

Mol. Cell. Biol.

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We have further analyzed the metabolism of specific messenger ribonucleic acid (mRNA) sequences within the cytoplasmic and nuclear RNA of Chinese hamster ovary (CHO) cells by using a set of previously constructed complementary deoxyribonucleic acid (DNA) clones (Harpold et al., Cell 17:1025-1035, 1979 as specific molecular probes in a variety of RNA: DNA hybridization experiments. The majority of the labeled mRNA complementary to each of the nine clones was found in the polyribosomes, with some variatioii between individual sequences. The great majority of each specific mRNA labeled for 3 h or less was in the polyadenylated [poly(A)+] fraction. However, the amount of each sequence increased in the non-poly(A)+ [poly(A)-] fraction after very long label times, suggesting the derivation of the poly(A)-RNA from the poly(A)+ RNA. Eight of the nine mRNA's have cytoplasmic half-lives ranging from 8 to 14 h, whereas one of the mRNA's, the scarcest in the group, has a somewhat shorter half-life of approximately 3 h. The proportion of each of the specific long-lived mRNA's within the total labeled mRNA increased as a function of labeling time, indicating that a large fraction, probably greater than 50%, of the initially labeled poly(A)+ mRNA in CHO cells has a half-life of less than 3 h. A quantitative analysis of the kinetics of labeling of specific nuclear and cytoplasmic sequences indicated that a significant fraction of the mRNA sequences transcribed from genes containing these nine CHO sequences were successfully processed into mRNA. However, two of the CHO mRNA sequences were only partially conserved during nuclear processing to yield mnRNA. These studies demonstrated that events at two posttranscriptional levels, differential nuclear processing efficiency of different primary transcripts and cytoplasmic stability of different mRNA's, can be involved in the determination of the cytoplasmic concentrations of different mRNA's.The study of total cell ribonucleic acid (RNA) from cultured cells has provided numerous suggestions, but no definitive conclusions, about many phases of messenger RNA (mRNA) metabolism (5, 6). For example, based on the average ultraviolet target size, most mRNA molecules in HeLa cells and L cells appear to derive from larger heterogeneous nuclear RNAs (hnRNA's) (7-9). The majority of total mRNA in polysomes from a wide variety of cells appears to contain a 3'-terminal polyadenylic acid [poly(A)] segment (1,3,11,20

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“…Grady et al [20] have shown that steady-state mouse liver and cultured fibroblast mRNA contains sequences found in either the poly(A)-containing pool or the poly(A)-free pool. They found only a small percentage of the sequence complexity existing in both of the two pools.…”

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confidence: 99%

HeLa Cell Cytoplasmic mRNA Contains Three Classes of Sequences Predominantly Poly(A)‐Free, Predominantly Poly(A)‐Containing and Bimorphic

Milcarek

1979

European Journal of Biochemistry

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The mRNA species which exist in the HeLa cell polyribosomes in a form devoid of A sequences longer than 8 nucleotides constitute the poly(A)‐free class of mRNA. The rapidly labelled component of this mRNA class shares no measurable sequence homology with poly(A)‐containing RNA. If poly(A)‐free mRNA larger than 12 S labelled for 2 h in vivo is hybridized with total cellular DNA, it hybridizes primarily with single‐copy DNA. When a large excess of steady poly(A)‐containing RNA is added before hybridization of labelled poly(A)‐free RNA, no inhibition of hybridization occurs. This indicates the existence of a class of poly(A)‐free mRNA with no poly(A)‐containing counterpart. Some mRNA species can exist solely as poly(A)‐containing mRNAs. These mRNAs in HeLa cells are found almost exclusively in the mRNA species present only a few times per cell (scarce sequences). Some mRNA species can exist in two forms, poly(A)containing and lacking, as evidenced by the translation data in vitro of Kaufmann et al. [Proc. Natl Acad. Sci. U.S.A. 74, 4801–4805 (1977)]. In addition, if cDNA to total poly(A)‐containing mRNA is fractionated into abundant and scarce classes, 47 % of the scarce class cDNA can be readily hybridized with poly(A)‐free mRNA. 10 of the abundant cDNA to poly(A)‐containing mRNA will hybridize with poly(A)‐free sequences very rapidly while the other 90% hybridize 160 times more slowly, indicating two very different frequency distributions. The cytoplasmic metabolism of these three distinct mRNA classes is discussed.

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Complexity of poly(A⁺) and poly(A⁻) polysomal RNA in mouse liver and cultured mouse fibroblasts

Cited by 48 publications

References 28 publications

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

HeLa Cell Cytoplasmic mRNA Contains Three Classes of Sequences Predominantly Poly(A)‐Free, Predominantly Poly(A)‐Containing and Bimorphic

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Complexity of poly(A+) and poly(A−) polysomal RNA in mouse liver and cultured mouse fibroblasts

Cited by 48 publications

References 28 publications

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Complexity and content of the DNA and RNA in Trypanosoma cruzi

Chinese hamster polyadenylated messenger ribonucleic acid: relationship to non-polyadenylated sequences and relative conservation during messenger ribonucleic acid processing.

HeLa Cell Cytoplasmic mRNA Contains Three Classes of Sequences Predominantly Poly(A)‐Free, Predominantly Poly(A)‐Containing and Bimorphic

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Complexity of poly(A⁺) and poly(A⁻) polysomal RNA in mouse liver and cultured mouse fibroblasts