TY - JOUR
T1 - The Sequence Dependent Nanoscale Structure of CENP-A Nucleosomes
AU - Stormberg, Tommy
AU - Lyubchenko, Yuri L.
N1 - Funding Information:
The work was supported by grants to Y.L.L. from NSF (MCB 1515346 and MCB 2123637). T.S. was partially supported by the SBMB Fellowship through funding from the Department of Education Graduate Assistance in Areas of National Need (GAANN) program.
Publisher Copyright:
© 2022 by the authors.
PY - 2022/10
Y1 - 2022/10
N2 - CENP-A is a histone variant found in high abundance at the centromere in humans. At the centromere, this histone variant replaces the histone H3 found throughout the bulk chromatin. Additionally, the centromere comprises tandem repeats of α-satellite DNA, which CENP-A nucleosomes assemble upon. However, the effect of the DNA sequence on the nucleosome assembly and centromere formation remains poorly understood. Here, we investigated the structure of nucleosomes assembled with the CENP-A variant using Atomic Force Microscopy. We assembled both CENP-A nucleosomes and H3 nucleosomes on a DNA substrate containing an α-satellite motif and characterized their positioning and wrapping efficiency. We also studied CENP-A nucleosomes on the 601-positioning motif and non-specific DNA to compare their relative positioning and stability. CENP-A nucleosomes assembled on α-satellite DNA did not show any positional preference along the substrate, which is similar to both H3 nucleosomes and CENP-A nucleosomes on non-specific DNA. The range of nucleosome wrapping efficiency was narrower on α-satellite DNA compared with non-specific DNA, suggesting a more stable complex. These findings indicate that DNA sequence and histone composition may be two of many factors required for accurate centromere assembly.
AB - CENP-A is a histone variant found in high abundance at the centromere in humans. At the centromere, this histone variant replaces the histone H3 found throughout the bulk chromatin. Additionally, the centromere comprises tandem repeats of α-satellite DNA, which CENP-A nucleosomes assemble upon. However, the effect of the DNA sequence on the nucleosome assembly and centromere formation remains poorly understood. Here, we investigated the structure of nucleosomes assembled with the CENP-A variant using Atomic Force Microscopy. We assembled both CENP-A nucleosomes and H3 nucleosomes on a DNA substrate containing an α-satellite motif and characterized their positioning and wrapping efficiency. We also studied CENP-A nucleosomes on the 601-positioning motif and non-specific DNA to compare their relative positioning and stability. CENP-A nucleosomes assembled on α-satellite DNA did not show any positional preference along the substrate, which is similar to both H3 nucleosomes and CENP-A nucleosomes on non-specific DNA. The range of nucleosome wrapping efficiency was narrower on α-satellite DNA compared with non-specific DNA, suggesting a more stable complex. These findings indicate that DNA sequence and histone composition may be two of many factors required for accurate centromere assembly.
KW - CENP-A nucleosomes
KW - alpha satellite DNA
KW - atomic force microscopy
KW - centromere chromatin
KW - nanoscale structure of nucleosomes
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U2 - 10.3390/ijms231911385
DO - 10.3390/ijms231911385
M3 - Article
C2 - 36232691
AN - SCOPUS:85139944742
VL - 23
JO - International Journal of Molecular Sciences
JF - International Journal of Molecular Sciences
SN - 1661-6596
IS - 19
M1 - 11385
ER -