0000000000301189
AUTHOR
Anu Aaspöllu
Impairment of intracellular antiviral defense with age: age-dependent changes in expression of interferon-induced and double-stranded RNA-activated 2-5A synthetase in rat.
The 2',5'-oligoadenylate (2-5A) system is involved in the defense of mammalian cells against virus infection. In a previous study [25], we demonstrated that the activities of the enzymes which synthesize and degrade 2-5A [2-5A synthetase (2-5OAS) and 2',3'-exoribonuclease] and of the enzyme that is activated by 2-5A (ribonuclease L) change during aging and development in different tissues of rat. The age-dependent decrease in 2-5OAS activity and increase in 2-5A nuclease activity results in a decrease in the cellular 2-5A content, suggesting that the efficiency of the antiviral 2-5A system is impaired in aged rats. Here we determined the age-dependent changes in the level of mRNA coding for…
Homologies Between Different Forms of 2-5A Synthetases
(2′-5′) Oligoadenylate synthetases (2-5A synthetases; EC 2.7.7.19) are present in mammalian cells and tissues and synthesize from ATP a series of oligomers termed 2-5A [general formula: ppp(A2′p)nA; with 1 ≤ n < 18 and usually 1 ≤ n < 6] (Hovanessian 1991). For full enzymic activity of the 2-5A synthetases, binding of double-stranded RNA is required (Sen 1982). Three principal 2-5A synthetase isoenzymes have been described with Mr’s of 40–46, 69, and 100 kDa (Chebath et al. 1987; Hovanessian et al. 1987, 1988). In the following they are classified as 2-5A synthetase I [Mr 40–46 000], II [Mr 69 000] and III [Mr 100 000]. All three isoforms are induced in cells by interferon (Cohen et al. 198…