1 Department of Morphological and Biomedical Sciences, Anatomy and Histology Section, University of Verona, Verona, Italy.
DNA Cell Biol. 2010 Feb;29(2):49-57. doi: 10.1089/dna.2009.0880.
We previously described an unusual accumulation of perichromatin fibrils (PF)-the in situ form of pre-mRNA transcription and early splicing-in hepatocyte nuclei of old rats. Here we have investigated, by immunoelectron microscopy, the nature of such PF, analyzing the presence of transcription, splicing and cleavage factors, polyadenylated RNA, and the incorporation of bromouridine in adult and old rats. Our observations revealed alterations in amount and/or distribution of pre-mRNA transcription, splicing and cleavage factors, as well as of polyadenylated RNA, together with lower bromouridine incorporation in newly transcribed RNA in the hepatocyte nucleoplasm of old rats. Therefore, our data indicate both a decrease in pre-mRNA transcription and a slow down of PF processing and transport during aging.
我们之前描述了一种在老年大鼠肝细胞核中出现的异常的染色质纤维（PF）聚集，这是前体 mRNA 转录和早期剪接的原位形式。在这里，我们通过免疫电子显微镜分析了这种 PF 的性质，研究了转录、剪接和切割因子、多聚腺苷酸化 RNA 以及溴尿嘧啶核苷在成年和老年大鼠中的掺入情况。我们的观察结果表明，老年大鼠肝细胞核质中前体 mRNA 转录、剪接和切割因子以及多聚腺苷酸化 RNA 的数量和/或分布发生了改变，同时新转录的 RNA 中溴尿嘧啶核苷的掺入也减少了。因此，我们的数据表明，在衰老过程中，前体 mRNA 转录减少，PF 的加工和运输减慢。
