Centromeres are specified epigenetically by the incorporation of the histone H3 variant CENP-A. In humans, amphibians, and fungi, CENP-A is deposited at centromeres by the HJURP/Scm3 family of assembly factors, but homologues of these chaperones are absent from a number of major eukaryotic lineages such as insects, fish, nematodes, and plants. In Drosophila, centromeric deposition of CENP-A requires the fly-specific protein CAL1. Here, we show that targeting CAL1 to noncentromeric DNA in Drosophila cells is sufficient to heritably recruit CENP-A, kinetochore proteins, and microtubule attachments. CAL1 selectively interacts with CENP-A and is sufficient to assemble CENP-A nucleosomes that display properties consistent with left-handed octamers. The CENP-A assembly activity of CAL1 resides within an N-terminal domain, whereas the C terminus mediates centromere recognition through an interaction with CENP-C. Collectively, this work identifies the "missing" CENP-A chaperone in flies, revealing fundamental conservation between insect and vertebrate centromere-specification mechanisms.
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http://dx.doi.org/10.1083/jcb.201305036 | DOI Listing |
Int J Mol Sci
December 2024
Department of Pharmaceutical Sciences, University of Nebraska Medical Center, Omaha, NE 68198-6025, USA.
In eukaryotic nuclei, DNA is wrapped around an octamer of core histones to form nucleosomes. H1 binds to the linker DNA of nucleosome to form the chromatosome, the next structural unit of chromatin. Structural features on individual chromatosomes contribute to chromatin structure, but not fully characterized.
View Article and Find Full Text PDFSci Rep
January 2025
Department of Surgical Oncology II, The General Hospital of Ningxia Medical University, 804 Shengli Street, Yinchuan, Ningxia, 750004, China.
Non-small cell lung adenocarcinoma (LUAD) is a markedly heterogeneous disease, with its underlying molecular mechanisms and prognosis prediction presenting ongoing challenges. In this study, we integrated data from multiple public datasets, including TCGA, GSE31210, and GSE13213, encompassing a total of 867 tumor samples. By employing Mendelian randomization (MR) analysis, machine learning techniques, and comprehensive bioinformatics approaches, we conducted an in-depth investigation into the molecular characteristics, prognostic markers, and potential therapeutic targets of LUAD.
View Article and Find Full Text PDFThe chromatin of the centromere provides the assembly site for the mitotic kinetochore that couples microtubule attachment and force production to chromosome movement in mitosis. The chromatin of the centromere is specified by nucleosomes containing the histone H3 variant CENP-A. The constitutive centromeric-associated network (CCAN) and kinetochore are assembled on CENP-A chromatin to enable chromosome separation.
View Article and Find Full Text PDFNature
January 2025
Department of Biological Sciences, The University of Tokyo, Tokyo, Japan.
In organisms ranging from vertebrates to plants, major components of centromeres are rapidly evolving repeat sequences, such as tandem repeats (TRs) and transposable elements (TEs), which harbour centromere-specific histone H3 (CENH3). Complete centromere structures recently determined in human and Arabidopsis suggest frequent integration and purging of retrotransposons within the TR regions of centromeres. Despite the high impact of 'centrophilic' retrotransposons on the paradox of rapid centromere evolution, the mechanisms involved in centromere targeting remain poorly understood in any organism.
View Article and Find Full Text PDFSci Adv
January 2025
Department of Ecology and Evolution, University of Lausanne, 1015 Lausanne, Switzerland.
Centromeres are essential for chromosome segregation in eukaryotes, yet their specification is unexpectedly diverse among species and can involve major transitions such as those from localized to chromosome-wide centromeres between monocentric and holocentric species. How this diversity evolves remains elusive. We discovered within-cell variation in the recruitment of the major centromere protein CenH3, reminiscent of variation typically observed among species.
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