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4‐THIOURIDINE INCORPORATION INTO THE RNA OF MONKEY KIDNEY CELLS (CV‐1) TRIGGERS NEAR‐UV LIGHT LONG‐TERM INHIBITION OF DNA, RNA AND PROTEIN SYNTHESIS
Author(s) -
Favre Alain,
Moreno Giuliana,
Salet Christian,
Vinzens Francloise
Publication year - 1993
Publication title -
photochemistry and photobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.818
H-Index - 131
eISSN - 1751-1097
pISSN - 0031-8655
DOI - 10.1111/j.1751-1097.1993.tb04953.x
Subject(s) - rna , dna , protein biosynthesis , dna synthesis , microbiology and biotechnology , chemistry , term (time) , biophysics , biology , biochemistry , gene , physics , quantum mechanics
Abstract Monkey kidney cells (CV‐1) grown for 4 h in the presence of 0.1 m M 4‐thiouridine (s 4 Urd) incorporate this photoactivable uridine analog in their RNA. A minor, 5–8%, thiolated RNA fraction can be isolated from bulk RNA by affinity chromatography. This RNA fraction contains 1.5–2.5 s 4 Urd residues per 100 nucleotides and exhibits a broad chain length distribution ranging from 700 to 7000 nucleotides. It is essentially of nuclear origin and amounts to 30% of the RNA synthesized during exposure of cells to s 4 Urd. Under the same s 4 Urd labeling conditions, no thiolated pyrimidine residues have been detected in DNA. Irradiation with 365 nm light (45 kJ/m 2 ) of the cells immediately after s 4 Urd exposure triggers long‐term inhibition of DNA, RNA and protein synthesis accompanied by a linear decline (50% in 2 days) in the total cell mass of cultured cells. In contrast, exposure to s 4 Urd alone results in moderate but reversible inhibitory effects. The available data suggest that s 4 Urd‐induced photolesions in newly synthesized RNA such as RNA‐RNA cross‐links as well as RNA‐protein bridges are directly involved in impairment of essential cellular functions.