Nucleosomes regulate the transcription output of the genome by occluding the underlying DNA sequences from DNA-binding proteins that must act on it. Knowledge of the precise locations of nucleosomes in the genome is thus essential towards understanding how transcription is regulated. Current nucleosome-mapping strategies involve digesting chromatin with nucleases or chemical cleavage followed by high-throughput sequencing. In this review, we compare the traditional micrococcal nuclease (MNase)-based approach with a chemical cleavage strategy, with discussion on the important insights each has uncovered about the role of nucleosomes in shaping transcriptional processes.

核小体通过遮挡必须作用于基因组的DNA结合蛋白中的基础DNA序列来调节基因组的转录输出。因此，了解核小体在基因组中的精确位置对于了解转录的调控方式至关重要。当前的核小体映射策略涉及用核酸酶或化学切割消化染色质，然后进行高通量测序。在这篇综述中，我们将传统的基于微球菌核酸酶（MNase）的方法与化学裂解策略进行了比较，并讨论了关于核小体在塑造转录过程中的作用的重要见解。