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RNA synthesis by nuclei and nucleoli from ischemic liver cells
Author(s) -
Schiaffonati Luisa,
Cairo Gaetano,
BernelliZazzera Aldo
Publication year - 1978
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1040970324
Subject(s) - nucleolus , rna , polymerase , dna synthesis , biology , rna polymerase , microbiology and biotechnology , rna polymerase i , endogeny , dna , biochemistry , nucleus , gene
Nuclei and nucleoli were isolated from rat livers subjected to an interruption of the blood supply for periods of different duration, as well as after restoration of the blood supply. They were assayed for RNA synthesis under conditions of diverse ionic strengths, and in the presence of an exogenous template, such as poly d (A–T), and actinomycin to inactivate the endogenous template; α‐amanitin was made used of to distinguish polymerase I and polymerase II dependent RNA synthesis. Nuclei and nucleoli from ischemic livers showed a severe impairment of RNA synthesis, which is likely to be due to decreased initiation frequency of the engaged polymerases, while free polymerases were essentially unchanged. Both form I and II polymerase were equally involved. After restoration of the blood supply RNA synthesis recovered with an overshooting well above normal levels of activity, lasting for at least 24 hours. Increased RNA synthesis was not followed by thymidine incorporation into DNA.