Abstract
Histogene-gene expression was studied during the cell cycle of continuously dividing HeLa S 3 cells and after stimulation of confluent monolyers of WI-38 human diploid fibroblasts to proliferate. The presence of histone-mRNA sequences was assayed by hybridization to a 3H-labelled single-stranded DNA complementary to histone-mRNA molecules. In HeLa S 3 cells histone-mRNA sequences were found in the nucleus and associated with polyribosomes during S-phase, but not during G 1-phase. Transcripts of S-phase chromatin contained histone-mRNA sequences, but those of G 1-phase chromatin did not. Similarly, in WI-38 cells association of histone-mRNA sequences with polyribosomes and transcription of histone-mRNA sequences from chromatin parallel DNA replication. Taken together these results suggest that the regulation of histone-gene expression resides, at least in part, at the transcriptional level. Chromatin reconstruction studies provide evidence that non-histone chromosomal proteins play a key role in activation of histone-gene transcription during the period of the cell cycle when DNA is replicated. Phosphate groups associated with the S-phase non-histone chromosomal proteins appear to be functionally involved in the control of histone-gene readout.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 137-163 |
| Number of pages | 27 |
| Journal | Biochemical Society Symposia |
| Volume | No. 42 |
| State | Published - 1977 |