Kinetic Complexity of Nuclear Poly(A)‐Containing RNA in Normal and Regenerating Rat Liver

Abstract

Poly(A)‐containing RNA isolated from liver nuclei of untreated rats and 3 h or 12 h after partial hepatectomy or sham operation was hybridized to the complementary DNAs (cDNAs). In the homologous reactions two major components could be seen. When compared to normal liver, the complexity of the least abundant class was lower in nuclei from livers 3 h after partial hepatectomy and was higher in those isolated 12 h after operation. The heterologous reactions revealed an increase of some abundant poly(A)‐containing sequences and a loss or dilution of rare sequences 3 h after operation. The latter effect was not specific to the regeneration process but occurred after laparotomy as well. 12 h after partial hepatectomy, however, about 10% new poly(A)‐containing sequences were detected, corresponding to about 5000 molecules of 4500 nucleotides length, which are unique to regenerating nuclei.

The appearance of new polyadenylated nuclear RNA sequences during rat-liver regeneration

“…Our results are very similar to those of Krieg et al (2) who found that after 12 hours of rat-liver regeneration a population of new sequences, equivalent to 5000 sequences of 4500 nucleotides in length, had appeared in the polyadenylated nuclear MA. Interestingly, they found that at 3 hours after partial hepatectomy there was a decrease in the nmber of sequences ressed in polyadenylated nuclear liA but that this occurred both in partially hepatectomised rats and in sham-operated rats.…”

“…Our previous results (1) showing that changes in frequency of various polyadenylated polysomal ElA sequences1 rather than qualitative differences9 occur during liver regeneration are spported in a recent paper by Scholla et al (20). The changes that we observed in nuclear M1A were also reported by Krieg et al (2). We can say, therefore, that the pre-replication or hypertrophic phase of liver regeneration is characterised by the appearance of new nucleus-confined poly(A)+ VA sequences and by changes in the relative abmdances of poly(A)+ RNA sequences en the polyscmes.…”

“…Similar results have been found by Krieg etal. (2) who showed that about 10% of polyadanylated MNA sequences were restricted to 12-hour regenerating rat-liver nuclei. This is in contrast to the situation on the polysomes in which only quatitative differences between normal and 16-iour regenerating rat liver could be detected (1).…”

Partial restriction of genome expression — a component of its work reprogramming in regenerating liver of mammals

“…Наличие такой взаимосвязи подтверждается не только данными, приведенными в табл. 1, но и полученными на животных другого возраста и вида [26][27][28] [33] Поли (A)+ядРрК [34] Поли (А) +полисомная РНК Г35] Поли (А)+ядРНК [35] Поли (А) +полисомная РНК [34] Примечание.ЧП, СП и УП соответственно часто-, среднеповторяющиеся и уникальные последовательности ДНК; дРНК 63 °С -РНК, полученная фенольным фракционированием при 63 °С. табл.…”

Nuclear RNA at the early stage of liver regeneration

“…Наиболее вероятным кажется третье предположение, правомерность которого показана для РНКбз° [13]. Помимо этого, увеличение числа копий транскриптов с УП обнаружено независимыми методами в составе ядерной поли(А)+РНК [11], так что, по-видимому, эта особенность дополняет характеристику раннего этапа регенерации.…”