The study, published in the journal Nature Genetics, was led by UCSF professor of biochemistry and biophysics Davide Ruggero and postdoctoral fellow Daniele Raices. The researchers used a combination of experimental techniques to measure the timing of DNA replication and to visualize the 3D structure of genes in living cells.
They found that genes that replicate early in the cell cycle tend to be located in regions of the nucleus that are more accessible to the DNA replication machinery. These genes also tend to have a more open and accessible chromatin structure, which makes them easier to transcribe into RNA.
In contrast, genes that replicate late in the cell cycle tend to be located in regions of the nucleus that are less accessible to the DNA replication machinery. These genes also tend to have a more compact and inaccessible chromatin structure, which makes them more difficult to transcribe into RNA.
The researchers believe that this relationship between DNA replication timing and gene folding may be important for regulating gene expression. By controlling the timing of DNA replication, cells can control the accessibility of genes to the transcription machinery, and thus control the levels of gene expression.
This finding could have important implications for understanding how the genome is organized and regulated, and for developing new treatments for diseases caused by DNA damage. For example, by targeting the DNA replication machinery, it may be possible to develop new drugs that can prevent or repair DNA damage and thus prevent or treat diseases such as cancer.
