衰老人胚肺成纤维细胞核及染色质的体外转录活性

TRANSCRIPTION ACTIVITY IN THE CHROMATIN OF OLD HUMAN FETAL FIBROBLAST CELLS

研究人胚肺成纤维细胞（简称2BS）核及染色质体外转录活性与代龄的关系。方法：用γ-^(32)PATP及~3H-UTP参入法测定衰老2BS细胞核及染色质的转录活性。结果：（1）衰老2BS细胞核的转录起始能力较年轻的下降44％（P＜0.01）；（2）衰老和年轻2BS细胞核内不与染色质结合的RNA聚合酶（RNP）转录活性无差异（P＞0．05），而与染色质结合的RNA聚合酶转录活性则随增龄明显下降（P＜0．01）；（3）衰老2BS染色质体外转录活性较年轻2BS下降58％（P＜0．01），对DNaseⅠ的敏感性也有所降低。结论：衰老2BS细胞核染色质结构的改变可能是转录活性下降的原因。

Objective: To study relationship between transcription activity of human fetal fibroblast cell (2BS)chromatin or nuclei and population doublings. Methods: By using incorporation of [γ-'p] ATP and 3H-UTP to determine transcription activity of nuclei and chormatin. Results: Initiation rate of transcription in old 2BS nuclei decreased 44% compared with that in the young one. No difference (P>0. 05) of transctiption activity of chromat in-unbound RNA polymerase in old and young 2BS unclei, but transcription activity of chromatin-bound RNA polymerase in old 2BS nuclei apparently decresed (P<0. 01). Transcription activity of chromatin in old 2BS decreased 58% compared with that in the young one, and its DNase Ⅰ digestion sensitivity also decreased. Conclusion: A significant decrease of transcription activity in nuclei and chromatin was showed during 2BS cell ageing.