POLY(ADENYLIC ACID)-CONTAINING AND POLY(ADENYLIC ACID)-DEFICIENT MESSENGER-RNA OF MOUSE-LIVER
POLY(ADENYLIC ACID)-CONTAINING AND POLY(ADENYLIC ACID)-DEFICIENT MESSENGER-RNA OF MOUSE-LIVER
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DOI:
10.1016/0005-2787(81)90221-5
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发表时间:
1981-01-01
期刊:
影响因子:
--
通讯作者:
DOYLE, D
中科院分区:
文献类型:
--
作者:
MOFFETT, RB;DOYLE, D
RNA was isolated and fractionated into poly(A)-containing and -deficient classes by oligo(dT) chromatography. Approximately 99% of the poly(A) material bound to the oligo(dT); that which did not bind contained substantially shorter poly(A) chains. All RNA fractions retained an ability to initiate cell-free translation, with the poly(A)-deficient fraction containing half the total translational activity, i.e., mRNA. Two-dimensional polyacrylamide gel analysis of the cell-free translation products revealed 3 classes of mRNA: mRNA preferentially containing poly(A), including the abundant liver mRNA species; poly(A)-deficient mRNA, including many mid- and low-abundant mRNA exhibiting less than 10% contamination in the poly(A)-containing fraction; and bimorphic species of mRNA proportioned between both the poly(A)-containing and -deficient fractions. Poly(A)-containing and bimorphic mRNA classes were further characterized by c[complementary]DNA hybridizations. The capacity of various RNA fractions to prime cDNA synthesis was determined. Compared to total RNA, the poly(A)-containing RNA retained 70% of the priming capacity, while 20% was found in the poly(A)-deficient fraction. Poly(A)-containing, poly(A)-deficient and total RNA fractions were hybridized to cDNA synthesized from (+)poly(A)RNA. Poly(A)-containing RNA hybridized with an average R0t1/2 [R0 = concentration of RNA; t1/2 = half-time of hybridization] approximately 20 times faster than total RNA. Poly(A)-deficient RNA hybridized with an average R0t1/2 approximately 3-4 times slower than total RNA. These R0t1/2 shifts indicated that in excess of 3/4 of the total hybridizable RNA was recovered in the poly(A)-containing fraction and that less than 1/4 was recovered in the poly(A)-deficient RNA fraction. Abundancy classes were less distinct in heterologous hybridizations. In all cases the extent of hybridization was similar, indicating that while the amount of various mRNA species varied among the RNA fractions, most hybridizing species of RNA were present in each RNA fraction. cDNA to the abundant class of mRNA was purified and hybridized to both (+)- and (-)poly(A)RNA. Messenger RNA corresponding to the more abundant species was enriched in the poly(A)-containing fraction at least 2-fold over the less abundant species of mRNA, with less than 10% of the abundant mRNA appearing in the poly(A)-deficient fraction.