Evidence that the V+ fibronectin mRNA is increased in the hippocampus of aged rats

In this study we investigated the splicing pattern of fibronectin (FN) mRNA during development and aging by using Northern blot hybridization with probes that either recognize all forms of FN mRNA or that are specific for the different spliced forms (FN-EIIIA, FN-EIIIB, and FN-V). We find that (1) the FNmRNA in the hippocampus of some but not all old rats showed a pattern of splicing similar to that found in the forebrain of 21 day old rats and (2) the hybridization signal for the alternatively spliced FN mRNA containing the EIIIA, EIIIB, and V95 segments was relatively abundant at early postnatal stages but very few transcripts were detected in adult and old rats. However, the hybridization signal for the juvenile FN-V mRNA was markedly increased in some but not all two-year-old rats suggesting that aging is an individual process.