NCM 2022: Determination of the centromere protein A landscape at single-molecule resolution

Centromere protein A (CENP-A) is a histone H3 variant that specifies the location of each chromosome’s centromere, which is essential for proper kinetochore attachment and chromosome segregation. Mislocalisation and misregulation of CENP-A can drive chromosomal breakage and rearrangement, leading to cancer and chromosomal aneuploidies. Measuring and comparing the density and spacing of CENP-A-containing nucleosomes within and between endogenous human centromeres will provide new insight into the structure of the inner kinetochore, as well as how this structure helps to ensure proper centromeric function and strength.
Recently, directed methylation with long-read sequencing (DiMeLo-seq) was developed, which deposits exogenous adenine methylation marks near a desired protein then uses nanopore long-read sequencing to quantify this exogenous adenine methylation directly along with endogenous cytosine methylation. Here, we present the distribution of CENP-A on ultra-long single molecules using DiMeLo-seq in the HG002 cell line. Furthermore, we discuss a probabilistic algorithm for predicting the positions of single CENP-A nucleosomes on single chromatin fibers.