Centromere Protein Research Articles

NMR study of the structure and dynamics of the BRCT domain from the kinetochore protein KKT4

KKT4 is a multi-domain kinetochore protein specific to kinetoplastids, such as Trypanosoma brucei. It lacks significant sequence similarity to known kinetochore proteins in other eukaryotes. Our recent X-ray structure of the C-terminal region of KKT4 shows that it has a tandem BRCT (BRCA1 C Terminus) domain fold with a sulfate ion bound in a typical binding site for a phosphorylated serine or threonine. Here we present the 1H, 13C and 15N resonance assignments for the BRCT domain of KKT4 (KKT4463–645) from T. brucei. We show that the BRCT domain can bind phosphate ions in solution using residues involved in sulfate ion binding in the X-ray structure. We have used these assignments to characterise the secondary structure and backbone dynamics of the BRCT domain in solution. Mutating the residues involved in phosphate ion binding in T. brucei KKT4 BRCT results in growth defects confirming the importance of the BRCT phosphopeptide-binding activity in vivo. These results may facilitate rational drug design efforts in the future to combat diseases caused by kinetoplastid parasites.

The noncanonical function of borealin, a component of chromosome passenger complex, promotes glycolysis via stabilization of survivin in squamous cell carcinoma cells

The chromosome passenger complex (CPC) is a kinase complex formed by Aurora B, borealin, survivin and inner centromere protein (INCENP). The CPC is active during mitosis and contributes to proper chromosome segregation via the phosphorylation of various substrates. Overexpression of each CPC component has been reported in most cancers. However, its significance remains unclear, as only survivin is known to confer chemoresistance. This study showed that the overexpression of borealin, a CPC component, stabilized survivin protein depending on its interaction with survivin. Unexpectedly, the accumulation of survivin by borealin overexpression did not affect the well-characterized functions of survivin, such as chemoresistance and cell proliferation. Interestingly, the overexpression of borealin promoted lactate production but not the overexpression of the deletion mutant that lacks the ability to bind to survivin. Consistent with these findings, the expression levels of glycolysis-related genes were enhanced in borealin-overexpressing cancer cells. Meanwhile, the overexpression of survivin alone did not promote lactate production. Overall, the accumulation of the borealin–survivin complex promoted glycolysis in squamous cell carcinoma cells. This mechanism may contribute to cancer progression via excessive lactate production.

Phosphorylation of Rec8 cohesin complexes regulates mono-orientation of kinetochores in meiosis I.

In meiosis I, unlike in mitosis, sister kinetochores are captured by microtubules emanating from the same spindle pole (mono-orientation) and centromeric cohesion mediated by cohesin is protected in the following anaphase I. The conserved meiosis-specific kinetochore protein meikin (Moa1 in fission yeast) associates with polo-like kinase: Plo1 and regulates both mono-orientation and cohesion protection. Although the phosphorylation of Rec8-S450 by Plo1 associated with Moa1 plays a key role in cohesion protection, how Moa1-Plo1 regulates mono-orientation remains elusive. Here, we identify Plo1 phosphorylation sites in the cohesin subunits, Rec8 and Psm3. The non-phosphorylatable mutations at these sites showed specific defects in mono-orientation. These results enabled the genetic dissection of meikin functions at the centromeres.

KNL1 and NDC80 represent new universal markers for the detection of functional centromeres in plants.

Centromere is the chromosomal site of kinetochore assembly and microtubule attachment for chromosome segregation. Given its importance, markers that allow specific labeling of centromeric chromatin throughout the cell cycle and across all chromosome types are sought for facilitating various centromere studies. Antibodies against the N-terminal region of CENH3 are commonly used for this purpose, since CENH3 is the near-universal marker of functional centromeres. However, because the N-terminal region of CENH3 is highly variable among plant species, antibodies directed against this region usually function only in a small group of closely related species. As a more versatile alternative, we present here antibodies targeted to the conserved domains of two outer kinetochore proteins, KNL1 and NDC80. Sequence comparison of these domains across more than 350 plant species revealed a high degree of conservation, particularly within a six amino acid motif, FFGPVS in KNL1, suggesting that both antibodies would function in a wide range of plant species. This assumption was confirmed by immunolabeling experiments in angiosperm (monocot and dicot) and gymnosperm species, including those with mono-, holo-, and meta-polycentric chromosomes. In addition to centromere labeling on condensed chromosomes during cell division, both antibodies detected the corresponding regions in the interphase nuclei of most species tested. These results demonstrated that KNL1 and NDC80 are better suited for immunolabeling centromeres than CENH3, because antibodies against these proteins offer incomparably greater versatility across different plant species which is particularly convenient for studying the organization and function of the centromere in non-model species.

Fluorescence complementation-based FRET imaging reveals centromere assembly dynamics.

Visualization of specific molecules and their assembly in real time and space is essential to delineate how cellular dynamics and signaling circuit are orchestrated during cell division cycle. Our recent studies reveal structural insights into human centromere-kinetochore core CCAN complex. Here we introduce a method for optically imaging trimeric and tetrameric protein interactions at nanometer spatial resolution in live cells using fluorescence complementation-based Förster resonance energy transfer (FC-FRET). Complementary fluorescent protein molecules were first used to visualize dimerization followed by FRET measurements. Using FC-FRET, we visualized centromere CENP-SXTW tetramer assembly dynamics in live cells, and dimeric interactions between CENP-TW dimer and kinetochore protein Spc24/25 dimer in dividing cells. We further delineated the interactions of monomeric CENP-T with Spc24/25 dimer in dividing cells. Surprisingly, our analyses revealed critical role of CDK1 kinase activity in the initial recruitment of Spc24/25 by CENP-T. However, interactions between CENP-T and Spc24/25 during chromosome segregation is independent of CDK1. Thus, FC-FRET provides a unique approach to delineate spatiotemporal dynamics of trimerized and tetramerized proteins at nanometer scale and establishes a platform to report the precise regulation of multimeric protein interactions in space and time in live cells.

Influence of different pH milieu on the structure and function of human Aurora kinase B protein (AURK-B): Amalgamation of both spectroscopic and computational approach

Aurora kinase B (AURK-B) is a serine/threonine kinase protein that plays an essential role in chromosomal separation during the cell cycle event. AURK-B is highly expressed in various types of cancer such as human seminoma, thyroid carcinoma, non-small cell lung carcinoma (NSCLC), oral carcinoma, and gastric cancer. Hence, it is a potential therapeutic target in the treatment of various cancers. The structure of AURK-B in complex with one of its substrate inner centromeric protein (INCENP) is present, but the structural and functional characterization of native AURK-B at different pH environment is still unexplored.This study determines the effect of different pH milieu on the structure and function of AURK-B protein wherein the influence of pH on the protein conformation was probed using Circular dichroism (CD) and fluorescence spectroscopy. The structural studies were further combined with functional activity assay to observe the change in kinase activity at various pH milieu (2.0–11.0). CD and fluorescence spectroscopy experiments dictate that at high acidic conditions (pH 2.0 – 5.0), the secondary and tertiary structures of AURK-B become distorted, leading to diminished activity. The protein, however, was observed to stabilize towards pH 7.0 – 8.0 with minimal structure alteration over the basic pH range (pH 9.0 –11.0). The measured spectroscopic structural features were found to be in-line with obtained experimental kinase activity assays.Further, in-vitro experiments indicate that the enzyme is maximally active at pH 8.0. More ordered conformation and compact structure was observed at this pH (pH 8.0) as compared to other pH values through molecular dynamics simulation studies (MDS). As AURK-B localizes itself in the intracellular compartment, this study may provide a clue about the role of different pH environments in enhancing cancer growth, proliferation, and invasion.

A conserved CENP-E region mediates BubR1-independent recruitment to the outer corona at mitotic onset

The outer corona plays an essential role at the onset of mitosis by expanding to maximize microtubule attachment to kinetochores.1,2 The low-density structure of the corona forms through the expansion of unattached kinetochores. It comprises the RZZ complex, the dynein adaptor Spindly, the plus-end directed microtubule motor centromere protein E (CENP-E), and the Mad1/Mad2 spindle-assembly checkpoint proteins.3,4,5,6,7,8,9,10 CENP-E specifically associates with unattached kinetochores to facilitate chromosome congression,11,12,13,14,15,16 interacting with BubR1 at the kinetochore through its C-terminal region (2091-2358).17,18,19,20,21 We recently showed that CENP-E recruitment to BubR1 at the kinetochores is both rapid and essential for correct chromosome alignment. However, CENP-E is also recruited to the outer corona by a second, slower pathway that is currently undefined.19 Here, we show that BubR1-independent localization of CENP-E is mediated by a conserved loop that is essential for outer-corona targeting. We provide a structural model of the entire CENP-E kinetochore-targeting domain combining X-ray crystallography and Alphafold2. We reveal that maximal recruitment of CENP-E to unattached kinetochores critically depends on BubR1 and the outer corona, including dynein. Ectopic expression of the CENP-E C-terminal domain recruits the RZZ complex, Mad1, and Spindly, and prevents kinetochore biorientation in cells. We propose that BubR1-recruited CENP-E, in addition to its essential role in chromosome alignment to the metaphase plate, contributes to the recruitment of outer corona proteins through interactions with the CENP-E corona-targeting domain to facilitate the rapid capture of microtubules for efficient chromosome alignment and mitotic progression.

Transcriptome-Wide N6-Methyladenosine Alternations in Pulmonary Arteries of Monocrotaline-Induced Pulmonary Arterial Hypertension in Rats and Novel Therapeutic Targets.

N6-methyladenosine (m6A) is a post-transcriptional epigenetic change with transcriptional stability and functionality regulated by specific m6A-modifying enzymes. However, the significance of genes modified by m6A and enzymes specific to m6A regulation in the context of pulmonary arterial hypertension (PAH) remains largely unexplored. MeRIP-seq and RNA-seq were applied to explore variances in m6A and RNA expression within the pulmonary artery tissues of control and monocrotaline-induced PAH rats. Functional enrichments were analyzed using the Gene Ontology and Kyoto Encyclopedia of Genes and Genomes. To screen candidate m6A-related genes, the STRING and Metascape databases were used to construct a protein-protein interaction network followed by a real-time PCR validation of their expression. The expression level of an m6A regulator was further investigated using immunohistochemical staining, immunofluorescence, and Western blot techniques. Additionally, proliferation assays were conducted on primary rat pulmonary artery smooth muscle cells (PASMCs). We identified forty-two differentially expressed genes that exhibited either hypermethylated or hypomethylated m6A. These genes are predominantly related to the extracellular matrix structure, MAPK, and PI3K/AKT pathways. A candidate gene, centromere protein F (CENPF), was detected with increased expression in the PAH group. Additionally, we first identified an m6A reader, leucine rich pentatricopeptide repeat containing (LRPPRC), which was downregulated in the PAH rat model. The in vitro downregulation of Lrpprc mediated by siRNA resulted in the enhanced proliferation and elevated expression of Cenpf mRNA in primary rat PASMCs. Our study revealed a modified transcriptome-wide m6A landscape and associated regulatory mechanisms in the pulmonary arteries of PAH rats, potentially offering a novel target for therapeutic strategies in the future.

Single-cell RNA sequencing analysis identifies one subpopulation of endothelial cells that proliferates and another that undergoes the endothelial-mesenchymal transition in regenerating pig hearts.

Background: In our previous work, we demonstrated that when newborn pigs undergo apical resection (AR) on postnatal day 1 (P1), the animals' hearts were completely recover from a myocardial infarction (MI) that occurs on postnatal day 28 (P28); single-nucleus RNA sequencing (snRNAseq) data suggested that this recovery was achieved by regeneration of pig cardiomyocyte subpopulations in response to MI. However, coronary vasculature also has a key role in promoting cardiac repair. Method: Thus, in this report, we used autoencoder algorithms to analyze snRNAseq data from endothelial cells (ECs) in the hearts of the same animals. Main results: Our results identified five EC clusters, three composed of vascular ECs (VEC1-3) and two containing lymphatic ECs (LEC1-2). Cells from VEC1 expressed elevated levels of each of five cell-cyclespecific markers (Aurora Kinase B [AURKB], Marker of Proliferation Ki-67 [MKI67], Inner Centromere Protein [INCENP], Survivin [BIRC5], and Borealin [CDCA8]), as well as a number of transcription factors that promote EC proliferation, while (VEC3 was enriched for genes that regulate intercellular junctions, participate in transforming growth factor β (TGFβ), bone morphogenic protein (BMP) signaling, and promote the endothelial mesenchymal transition (EndMT). The remaining VEC2 did not appear to participate directly in the angiogenic response to MI, but trajectory analyses indicated that it may serve as a reservoir for the generation of VEC1 and VEC3 ECs in response to MI. Notably, only the VEC3 cluster was more populous in regenerating (i.e., ARP1MIP28) than non-regenerating (i.e., MIP28) hearts during the 1-week period after MI induction, which suggests that further investigation of the VEC3 cluster could identify new targets for improving myocardial recovery after MI. Histological analysis of KI67 and EndMT marker PDGFRA demonstrated that while the expression of proliferation of endothelial cells was not significantly different, expression of EndMT markers was significantly higher among endothelial cells of ARP1MIP28 hearts compared to MIP28 hearts, which were consistent with snRNAseq analysis of clusters VEC1 and VEC3. Furthermore, upregulated secrete genes by VEC3 may promote cardiomyocyte proliferation via the Pi3k-Akt and ERBB signaling pathways, which directly contribute to cardiac muscle regeneration. Conclusion: In regenerative heart, endothelial cells may express EndMT markers, and this process could contribute to regeneration via a endothelial-cardiomyocyte crosstalk that supports cardiomyocyte proliferation.

Immune infiltration related CENPI associates with the malignant features and drug resistance of lung adenocarcinoma

Centromere protein I (CENPI) is an important member of centromeric proteins family, which is crucial to chromosome alignment and segregation. Nevertheless, the interrelation between CENPI expression and tumor progression is in the shadows. In this reserch, we carried out a panoramic bioinformatic analysis about CENPI with TCGA, Timer 2.0, Oncomine, GEPIA, Cbioportal, LinkedOmics and CancerSEA databases. Besides, our bioinformatic results have been further confirmed through in vitro experiments, including Real-Time quantitative PCR (RT-qPCR), immunofluorescence (IF), immunohistochemistry (IHC), western blotting (WB), cell proliferation assays, EdU, cell cycle and apoptosis test. Our results suggested that CENPI was increased in most of the cancers, and may serve as a potential biomarker. What's more, the knock down of CENPI inhibited the expression of CDK2 in lung adenocarcinoma (LUAD), and resulted in the arrest of G0/G1 phase and apoptosis. Besides, CENPI was related to immune cells infiltration and drug sensitivity in pan-cancer, and can act as a potential treatment target to cure cancer patients.

CENPA knockdown restrains cell progression and tumor growth in breast cancer by reducing PLA2R1 promoter methylation and modulating PLA2R1/HHEX axis.

Breast cancer is a lethal malignancy affecting females worldwide. It has been reported that upregulated centromere protein A (CENPA) expression might indicate unfortunate prognosis and can function as a prognostic biomarker in breast cancer. This study aimed to investigate the accurate roles and downstream mechanisms of CENPA in breast cancer progression. CENPA protein levels in breast cancer tissues and cell lines were analyzed by Western blot and immunohistochemistry assays. We used gain/loss-of-function experiments to determine the potential effects of CENPA and phospholipase A2 receptor (PLA2R1) on breast cancer cell proliferation, migration, and apoptosis. Co-IP assay was employed to validate the possible interaction between CENPA and DNA methyltransferase 1 (DNMT1), as well as PLA2R1 and hematopoietically expressed homeobox (HHEX). PLA2R1 promoter methylation was determined using methylation-specific PCR assay. The biological capabilities of CENPA/PLA2R1/HHEX axis in breast cancer cells was determined by rescue experiments. In addition, CENPA-silenced MCF-7 cells were injected into mice, followed by measurement of tumor growth. CENPA level was prominently elevated in breast cancer tissues and cell lines. Interestingly, CENPA knockdown and PLA2R1 overexpression both restrained breast cancer cell proliferation and migration, and enhanced apoptosis. On the contrary, CENPA overexpression displayed the opposite results. Moreover, CENPA reduced PLA2R1 expression through promoting DNMT1-mediated PLA2R1 promoter methylation. PLA2R1 overexpression could effectively abrogate CENPA overexpression-mediated augment of breast cancer cell progression. Furthermore, PLA2R1 interacted with HHEX and promoted HHEX expression. PLA2R1 knockdown increased the rate of breast cancer cell proliferation and migration but restrained apoptosis, which was abrogated by HHEX overexpression. In addition, CENPA silencing suppressed tumor growth in vivo. CENPA knockdown restrained breast cancer cell proliferation and migration and attenuated tumor growth in vivo through reducing PLA2R1 promoter methylation and increasing PLA2R1 and HHEX expression. We may provide a promising prognostic biomarker and novel therapeutic target for breast cancer.

Upregulation of CENPM promotes breast carcinogenesis by altering immune infiltration

BackgroundThe involvement of centromere protein M (CENPM) in various types of cancer has been established, however, its impact on breast cancer and immune infiltration remains unknown.MethodsWe examined the expression of CENPM in different cancer types by utilizing the Cancer Genome Atlas (TCGA) and Genotype Tissue Expression Pan-Cancer (GEO) databases. Using data from the TCGA, we examined the correlation between the expression of CENPM, the prognosis, and the clinicopathological features of individuals diagnosed with breast cancer. We conducted an enrichment analysis of CENPM using the clusterProfiler R software tool, utilizing data obtained from breast cancer patients and specimens at our institution. In addition to examining the correlation between CENPM expression and genes associated with immune checkpoints, the TIDE algorithm was employed to explore the potential of CENPM as a biomarker for immunotherapy in breast cancer. The impact of CENPM on the growth of breast cancer cells was evaluated through the utilization of the CCK8 test and the colony formation assay. The effect of CENPM on the migration of breast cancer cells was assessed using scratch and transwell assays.ResultsResearch findings indicate that elevated levels of CENPM are linked to patient outcomes in breast cancer and various clinicopathological features. Furthermore, elevated levels of CENPM expression correlated with decreased levels of CD8 + T cells and mast cells, increased levels of Tregs and Th2, and reduced levels of CD8 + T cells. Additionally, the coexpression of CENPM with the majority of genes related to immune checkpoints indicates its potential to forecast the effectiveness of treatment in breast cancer. Suppression of CENPM hampers the growth and movement of breast tumor cells.ConclusionsIn summary, our study findings indicate that CENPM may serve as a cancer-causing gene in breast cancer and also as a biomarker for predicting the efficacy of immunotherapy.The oncogene CENPM is associated with breast cancer and is involved in cell proliferation and immune infiltration.

Abstract A003: HPV infection causes dependence on alternative DNA damage response pathways providing cancer specific targets for radiosensitization

Abstract Targeted radiosensitization is an attractive approach to improving the efficacy of radiotherapy in cancer treatment. However, drugs targeting ubiquitous DNA damage response (DDR) pathways are not cancer specific and can increase radiation related side effects. Thus, there is an unmet clinical need for tumor specific molecular targets. To address this need we sought to identify DNA damage signaling pathways that are unique to cancer cells. We hypothesized that by expressing its genome in host cells high-risk Human Papilloma Virus (HPV) can rewire DNA damage signaling making HPV-positive tumor cells dependent on alternative pathways to survive radiation, which can be exploited for targeted radiosensitization of HPV-induced cancers. Using a CRISPR/Cas9 screen in cells that selectively express HPV16 proteins E6 or E7 we uncovered genes that cells rely on to survive radiation-induced DNA damage in the context of E6 or E7 expression. We demonstrate that targeting these newly identified genes sensitizes cancer cells to radiation specifically in the presence of E6 or E7. We provide mechanistic insights showing that E6 and E7 alter the cellular epigenome by inhibiting histone lysine acetylation and tri-methylation, respectively. In this setting, a member of a centromeric protein complex identified in the screen is critical for mitotic progression and survival in E6-expressing cells following radiation exposure. Deletion of this factor resulted in delayed mitotic progression, chromosomal missegregation and rapid post-mitotic death in irradiated HPV-positive cells, a phenotype that was mitigated by ablation of E6 expression. Furthermore, we identified an E3 ubiquitin ligase that promotes survival in E7-expressing cells following radiation exposure by alleviating perturbations during DNA replication. Together, we have uncovered DDR pathways that are critical for cell survival after radiation exposure specifically in HPV-positive cells. Our findings suggest that expression of viral proteins E6 and E7 rewires DNA damage signaling networks causing dependence on alternative response pathways. We propose that these pathways can be targeted for tumor-specific radiosensitization of HPV-induced cancers. Citation Format: Michael Goldstein, Akhil Kotwal, Nishanth Gabriel, William Buchser, Monica Sentmanat, Stephanie Markovina, Julie Schwarz, Xia Cui. HPV infection causes dependence on alternative DNA damage response pathways providing cancer specific targets for radiosensitization [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: DNA Damage Repair: From Basic Science to Future Clinical Application; 2024 Jan 9-11; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2024;84(1 Suppl):Abstract nr A003.

Multimerization of a disordered kinetochore protein promotes accurate chromosome segregation by localizing a core dynein module.

Kinetochores connect chromosomes and spindle microtubules to maintain genomic integrity through cell division. Crosstalk between the minus-end directed motor dynein and kinetochore-microtubule attachment factors promotes accurate chromosome segregation by a poorly understood pathway. Here, we identify a linkage between the intrinsically disordered protein Spc105 (KNL1 orthologue) and dynein using an optogenetic oligomerization assay. Core pools of the checkpoint protein BubR1 and the adaptor complex RZZ contribute to the linkage. Furthermore, a minimal segment of Spc105 with a propensity to multimerize and which contains protein binding motifs is sufficient to link Spc105 to RZZ/dynein. Deletion of the minimal region from Spc105 compromises the recruitment of its binding partners to kinetochores and elevates chromosome missegregation due to merotelic attachments. Restoration of normal chromosome segregation and localization of BubR1 and RZZ requires both protein binding motifs and oligomerization of Spc105. Together, our results reveal that higher-order multimerization of Spc105 contributes to localizing a core pool of RZZ that promotes accurate chromosome segregation.

A coadapted KNL1 and spindle assembly checkpoint axis orchestrates precise mitosis in Arabidopsis.

The kinetochore scaffold 1 (KNL1) protein recruits spindle assembly checkpoint (SAC) proteins to ensure accurate chromosome segregation during mitosis. Despite such a conserved function among eukaryotic organisms, its molecular architectures have rapidly evolved so that the functional mode of plant KNL1 is largely unknown. To understand how SAC signaling is regulated at kinetochores, we characterized the function of the KNL1 gene in Arabidopsis thaliana. The KNL1 protein was detected at kinetochores throughout the mitotic cell cycle, and null knl1 mutants were viable and fertile but exhibited severe vegetative and reproductive defects. The mutant cells showed serious impairments of chromosome congression and segregation, that resulted in the formation of micronuclei. In the absence of KNL1, core SAC proteins were no longer detected at the kinetochores, and the SAC was not activated by unattached or misaligned chromosomes. Arabidopsis KNL1 interacted with SAC essential proteins BUB3.3 and BMF3 through specific regions that were not found in known KNL1 proteins of other species, and recruited them independently to kinetochores. Furthermore, we demonstrated that upon ectopic expression, the KNL1 homolog from the dicot tomato was able to functionally substitute KNL1 in A. thaliana, while others from the monocot rice or moss associated with kinetochores but were not functional, as reflected by sequence variations of the kinetochore proteins in different plant lineages. Our results brought insights into understanding the rapid evolution and lineage-specific connection between KNL1 and the SAC signaling molecules.

Higher-order protein assembly controls kinetochore formation.

To faithfully segregate chromosomes during vertebrate mitosis, kinetochore-microtubule interactions must be restricted to a single site on each chromosome. Prior work on pair-wise kinetochore protein interactions has been unable to identify the mechanisms that prevent outer kinetochore formation in regions with a low density of CENP-A nucleosomes. To investigate the impact of higher-order assembly on kinetochore formation, we generated oligomers of the inner kinetochore protein CENP-T using two distinct, genetically engineered systems in human cells. Although individual CENP-T molecules interact poorly with outer kinetochore proteins, oligomers that mimic centromeric CENP-T density trigger the robust formation of functional, cytoplasmic kinetochore-like particles. Both in cells and in vitro, each molecule of oligomerized CENP-T recruits substantially higher levels of outer kinetochore components than monomeric CENP-T molecules. Our work suggests that the density dependence of CENP-T restricts outer kinetochore recruitment to centromeres, where densely packed CENP-A recruits a high local concentration of inner kinetochore proteins.

The Correlation of Centromere Protein Q with Diagnosis and Prognosis in Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is one of the major types of liver cancer. Previous studies have shown that the centromere protein family is associated with malignant biological behaviors such as HCC proliferation. As a member of the centromere protein family, centromere protein Q (CENPQ) is closely associated with immunotherapy and immune cell infiltration in various tumors. However, the role and mechanism of CENPQ in HCC remain unclear. Multiple public databases and RT-qPCR were used to study the expression of CENPQ in HCC. Based on TCGA data, the correlation between CENPQ and clinicopathological characteristics and prognosis of HCC patients was analyzed, and its diagnostic value was evaluated. The potential biological functions of CENPQ in HCC were explored by functional enrichment analysis of differentially expressed genes. The distribution of tumor-infiltrating immune cell types was assessed using single-sample GSEA, and immune checkpoint gene expression was analyzed using Spearman correlation. Subsequently, loss-of-function experiments were performed to determine the function of CENPQ on the cell cycle and proliferation of HCC cells in vitro. CENPQ was found highly expressed in HCC and correlated with weight, BMI, age, AFP, T stage, pathologic stage, histologic grade, and prothrombin time (all p < 0.05). ROC and Kaplan-Meier analyses indicated that CENPQ may be potentially used as a diagnostic marker for HCC (AUC = 0.881), and its upregulation is associated with decreased OS (p = 0.002), DSS (p < 0.001), and PFI (p = 0.002). Functional enrichment analysis revealed an association of CENPQ with biological processes such as immune cell infiltration, cell cycle, and hippo-merlin signaling deregulation in HCC. Furthermore, knockdown of CENPQ manifested in HCC cells with G0/1 phase cycle arrest and decreased proliferative capacity. CENPQ expression was higher in HCC tissues than in normal liver tissues. It was significantly associated with poor prognosis, immune cell infiltration, cell cycle, and proliferation. Therefore, CENPQ may become a promising prognostic biomarker for HCC patients.

Plant kinetochore complex: composition, function, and regulation.

The kinetochore complex, an important protein assembly situated on the centromere, plays a pivotal role in chromosome segregation during cell division. Like in animals and fungi, the plant kinetochore complex is important for maintaining chromosome stability, regulating microtubule attachment, executing error correction mechanisms, and participating in signaling pathways to ensure accurate chromosome segregation. This review summarizes the composition, function, and regulation of the plant kinetochore complex, emphasizing the interactions of kinetochore proteins with centromeric DNAs (cenDNAs) and RNAs (cenRNAs). Additionally, the applications of the centromeric histone H3 variant (the core kinetochore protein CENH3, first identified as CENP-A in mammals) in the generation of ploidy-variable plants and synthesis of plant artificial chromosomes (PACs) are discussed. The review serves as a comprehensive roadmap for researchers delving into plant kinetochore exploration, highlighting the potential of kinetochore proteins in driving technological innovations in synthetic genomics and plant biotechnology.

Influence of TMX2-CTNND1 polymorphism on cortical thickness in schizophrenia patients and unaffected siblings: an exploratory study based on target region sequencing.

The advancement of neuroimaging and genetic research has revealed the presence of morphological abnormalities and numerous risk genes, along with their associations. We aimed to estimate magnetic resonance imaging-derived cortical thickness across multiple brain regions. The cortical thickness of 129 schizophrenia patients, 42 of their unaffected siblings, and 112 healthy controls was measured and the candidate genes were sequenced. Comparisons were made of cortical thickness (including 68 regions of the Desikan-Killiany Atlas) and genetic variants (in 108 risk genes for schizophrenia) among the three groups, and correlation analyses were performed regarding cortical thickness, clinical symptoms, cognitive tests (such as the N-back task and the logical memory test), and genetic variants. Schizophrenia patients had significantly thinner bilateral frontal, temporal, and parietal gyri than healthy controls and unaffected siblings. Association analyses in target genes showed that four single nucleotide variants (SNVs) were significantly associated with schizophrenia, including thioredoxin-related transmembrane protein 2-catenin, cadherin-associated protein, delta 1 (SNV20673) (positive false discovery rate [PFDR] = 0.008) and centromere protein M (rs35542507, rs41277477, rs73165153) (PFDR = 0.030). Additionally, cortical thickness in the right pars triangularis was lower in carriers of the SNV20673 variant than in non-carriers (PFDR = 0.048). Finally, a positive correlation was found between right pars triangularis cortical thickness and logical memory in schizophrenia patients (r = 0.199, p = 0.032). This study identified regional morphological abnormalities in schizophrenia, including the right homologue of Broca's area, which was associated with a risk variant that affected delta-1 catenin and logical memory. These findings suggest a potential association between candidate gene loci, cortical thickness, and schizophrenia.

A multidimensional analysis of ZW10 interacting kinetochore protein in human tumors

A multidimensional analysis of ZW10 interacting kinetochore protein in human tumors