|Budget Amount *help
¥2,100,000 (Direct Cost : ¥2,100,000)
Fiscal Year 1997 : ¥800,000 (Direct Cost : ¥800,000)
Fiscal Year 1996 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Previously, we showed that the expression of the fibronectin (FN) gene is enhanced during aging of human endothelial cells and fibroblasts. To elucidate the mechanism, we explored binding proteins to the FN promoter using ten different oligonucleotides for (potential) transcription factor-binding sites in the promoter. We observed increases in binding proteins to -20TATA,-40, -120, -150CAAT and -260CRE regions. To investigate that the changes may cause the enhancement of FN expression in senescent cells, we started a project to isolate proteins showing the increased bindings. However, this project is not going along with the previous schedule because the binding activity of these proteins is weak and multiple proteins bind to the respective region, and by other reasons. We are continuing the effort to isolate the proteins.
On the other hand, we isolated cDNA clones whose expression was eleated in senescent cells to elucidate the mechanism (s) of increase in expression of other genes during senescence. Among the clones, we found that eight clones were derived from four RNAs encoded by mitochondrial DNA.These are NADH dehyrogenase 2 (ND2), ND3, ATPaase 6 and 16S ribosomal RNA.We analyzed the expression level of these RNAs by Northern and slot hybridization using RNAs from young and senescent cells of two endothelial and two fibroblast cell strains. The result showed that the four genes were expressed higher in senescent endothelial and fibroblast cells than in the young counterparts. Analyzes of the enhanced expression of these mitochondrial and other genes isolated by us, together with that of fibronectin gene, will provide a resolution for the mechanism of senescence.