Fig. 6.

Western blot analysis of TnT3 and its fragments in young (3-month) and old (26–28-month) FVB mouse skeletal muscle. a TnT3 in TA whole muscle lysate, detected by a C-terminal-targeting antibody, shows decreased TnFL in old (O) compared to young (Y) mice. b TnFL expression was normalized to actin. c qPCR showing a slight decrease in TnT3, normalized to GADPH, mRNA in old (n = 5) compared to young (n = 6) mice. d Whole cell lysis (W) and nuclear protein fractions (N) from young and old mice were analyzed using TnT3 NT and CT antibodies. (e) The specific TnT3 N- and C-terminal regions targeted by the antibodies. f Normalized (against actin) TnNT, TnCT, and TnFL in the nuclear extracts were compared between young and old groups. TnCT tended to increase in the old nuclear extracts, and TnFL decreased dramatically (*P < 0.05, n = 3). TnNT did not change significantly. g The nuclear ratio between TnNT or TnCT and TnFL in both age groups was compared (**P = 0.012; ***P < 0.001, n = 3)