DNaseHypersensitivität

DNase hypersensitivity refers to regions of chromatin that are particularly susceptible to cleavage by the enzyme DNase I. These regions, known as DNase hypersensitive sites (DHSs), are typically found in the regulatory elements of genes, such as promoters and enhancers. The increased accessibility to DNase I indicates that the DNA in these regions is less tightly bound by nucleosomes, the protein complexes that package DNA in eukaryotes.

The open chromatin structure at DHSs suggests that these regions are actively involved in gene regulation. Transcription factors and other regulatory proteins can bind to these sites, influencing gene expression. Therefore, mapping DHSs provides a way to identify potential regulatory elements and understand how genes are controlled. The pattern of DHSs within a cell or tissue can be characteristic of its specific transcriptional state.

Techniques like DNase-seq (DNase I sequencing) are used to identify DHSs genome-wide. This method involves digesting genomic DNA with DNase I, sequencing the resulting short DNA fragments that are protected from digestion (representing the nucleosome-free regions), and then mapping these sequences back to the genome. Analyzing the distribution and intensity of DHSs can reveal insights into the epigenetic landscape and the regulatory networks governing cellular function.