Centromeric Regions Research Articles

Recombination landscape and karyotypic variations revealed by linkage mapping in the grapevine downy mildew pathogen Plasmopara viticola.

Plasmopara viticola, the causal agent of grapevine downy mildew, is a biotrophic oomycete engaged in a tight coevolutionary relationship with its host. Rapid adaptation of the pathogen is favored by annual sexual reproduction that generates genotypic diversity. With the aim of studying the recombination landscape across the P. viticola genome, we generated 2 half-sibling F1 progenies (N = 189 and 162). Using targeted SNP sequencing, between 1,405 and 1,894 markers were included in parental linkage maps, and a consensus map was obtained by integrating 4,509 markers. The reference genome could be assembled into 17 pseudochromosomes, anchoring 88% of its physical length. We observed a strong collinearity between parental genomes and extensive synteny with the downy mildew Peronospora effusa. In the consensus map, the median recombination rate was 13.8 cM/Mb. The local recombination rate was highly variable along chromosomes, and recombination was suppressed in putative centromeric regions. Recombination rate was found negatively correlated with repeats' coverage and positively correlated with gene coverage. However, genes encoding secreted proteins and putative effectors were underrepresented in highly recombining regions. In both progenies, about 5% of the individuals presented karyotypic anomalies. Aneuploidies and triploidies almost exclusively originated from the male-transmitted chromosomes. Triploids resulted from fertilization by diploid gametes, but also from dispermy. Obligatory sexual reproduction each year may explain the lower level of karyotypic variation in P. viticola compared to other oomycetes. The linkage maps will be useful to guide future de novo chromosome-scale assemblies of P. viticola genomes and to perform forward genetics.

PIT1/HINFI POLYMORPHISM IN HOLSTEIN CATTLE IN AFYONKARAHISAR PROVINCE

Pit1 gene has been shown to be located on the centromeric region of chromosome 1 in cattle. This gene has responsible for development of pituitary gland and hormone expression in mammals. Pit1 deficiency causes a dwarfism phenotype in mice, dogs and fish. Previous studies has demonstrated to associated with polymorphisms of the Pit1 gene and growth and reproductive performance and milk, meat yield traits. In the cattle, a HinfI polymorphism on Pit1 gene (c.1178G>A ) have been reported that there is an association between milk and reproduction yield parameters. In this study, we aimed existence and distribution of Pit1/HinfI polymorphism in 81 head of Holstein cattle in Afyonkarahisar province. In our study, we found that there were 5 AA, 30 AG and 46 GG genotypes in our survey population. We also detected to frequency of A allele as 0.25 and the G allele as 0.75. We calculated to genetic index values such as PIC (0.3027418) and Heterozygosity (0.3742044) using by RStudio package. Chi-square value was found 0.049 and was exhibited to survey population in Hardy-Weinberg equilibrium. Considering of these findings, we denoted proper of Pit1/HinfI polymorphism using in marker assisted selection studies both of native and culture cattle breeds.

Centromeres are hotspots for chromosomal inversions and breeding traits in mango.

Chromosomal inversions can preserve combinations of favorable alleles by suppressing recombination. Simultaneously, they reduce the effectiveness of purifying selection enabling deleterious alleles to accumulate. This study explores how areas of low recombination, including centromeric regions and chromosomal inversions, contribute to the accumulation of deleterious and favorable loci in 225 Mangifera indica genomes from the Australian Mango Breeding Program. Here, we identify 17 chromosomal inversions that cover 7.7% (29.7 Mb) of the M. indica genome: eight pericentric (inversion includes the centromere) and nine paracentric (inversion is on one arm of the chromosome). Our results show that these large pericentric inversions are accumulating deleterious loci, while the paracentric inversions show deleterious levels above and below the genome wide average. We find that despite their deleterious load, chromosomal inversions contain small effect loci linked to variation in crucial breeding traits. These results indicate that chromosomal inversions have likely facilitated the evolution of key mango breeding traits. Our study has important implications for selective breeding of favorable combinations of alleles in regions of low recombination.

Experimental in vivo models for understanding inter-molecular interactions and preventing multifactor disease development

The increased spontaneous fragility in the centromere regions of the chromosomes predisposes to abnormal cellular division due to abnormal interaction with the mitotic spindle, which leads to number chromosomal aberrations. The abnormal structure of the microtubule-associated proteins (MAPs) could also be among the internal factors, predisposing to these pathologies. On the other hand, the increased frequency of the spontaneous chromosomal fragility suggests abnormal structure of the respective chromosomal/chromatin components and thus an increased risk about gene mutations and structural chromosomal aberrations. The spontaneous chromosomal fragility was tested by light microscopy observation of metaphases from peripheral blood lymphocytes of 8 patients with polygene pathologies (neoplasms, neuro-degenerative diseases, and neuro-psychiatric disorders) and of 18 healthy controls. In the tested patients was established significantly higher frequency of the spontaneous chromosomal fragility, including in the centromere chromosomal regions, compared to the controls. Different inter-molecular interactions, which could prevent the pathology appearance, were investigated by appropriate experimental in vivo models. As a whole, in the most cases, the presented data showed significantly lower average titers of anti-ganglioside antibodies and gangliosides in the samples from myocardium and liver than in the samples from brain and pancreas. By taking into consideration that the myocardium and liver are known as the most enriched of GSH anatomic organs, the presented data could be explained with the literature messages of higher amounts of de novo-synthesized free GSH tri-peptide in the same two organs. Moreover, a possibility about the production of antibodies/immunoglobulins by non-lymphoid types of cells, tissues, and organs in appropriate conditions was shown. Because the so-produced antibodies are out of the germinative centers in the specialized lymphoid tissues and organs, the control of their functions by small ions and molecules as gangliosides is very important. In the current study, the attention was particularly directed to the iteractions with the participation of gangliosides, the reduced form of the tri-peptide glutathione (GSH), and the protein HACE1. Besides the tumor-suppressor activity of protein HACE1, also its neuroprotective influence was proven, namely by interactions with specific molecules.

Cytogenetic and <i>ISSR</i>-Markers Polymorphism in the Population of Local Ukrainian Lebedyn Cows

Preservation of the fund of local breeds of agricultural animals, which are breeding material for the creation of new ones and the improvement of existing ones, meets the requirements of the FAO - the protection of biological diversity. The study of the genetic structure of cows of the local Lebedyn breed, which was bred in Ukraine, with the use of cytogenetic and molecular genetic methods, is aimed at establishing information about the structure of the gene pool of these animals and the uniqueness of their genotype. Cytogenetic monitoring showed that the modal number of chromosomes corresponded to the species norm and was 2n=60, no constitutional abnormalities in the form of Robertsonian translocations were detected, the average frequency of genomic disorders (aneuploidy) was 10,2±2,10%, polyploidy was not manifested. structural disorders (chromosomal breaks) accounted for 3,1±1,88% and asynchronous separation of the centromeric regions of chromosomes – 0,8±0,10%. The average share of cytogenetic parameters of cells was determined: lymphocytes with micronucleus – 3,6±0,61‰, binucleus lymphocytes – 4,3±0,97‰ and mitotic index – 3,7±1,20‰. An analysis of the genetic structure of the local, small-numbered Lebedyn cattle breed of Ukraine was carried out using 8 ISSR-systems. All 8 microsatellite primers showed high efficiency. ISSR labeling revealed 88 amplified DNA fragments, of which only 18 were polymorphic. The total share of polymorphic loci was 25,45%. 11 species-specific loci for (ACC)6G, 5 loci for (CTC)6C, 10 for (GAG)6C, 7 for (GA)6CC, 10 for (AG)8CG, 9 for (AG)8CA, 13 for (GA)9C and 14 for (AG)9C. It was established that the studied animals were characterized by karyotype stability, reduced sensitivity to mutagenic factors of various nature, absence of inbreeding depression and reproductive isolation.

Karyotypes and chromosomal mapping of some repetitive DNAs in two stingless bee species (Apidae: Meliponini), with the description of a B chromosome in Plebeia genus.

Cytogenetic studies on stingless bees have significantly contributed to our understanding of karyotypic evolution and the composition of euchromatin and heterochromatin regions, including repetitive sequences. In this study, we performed classical cytogenetics, chromosomal banding, and mapping of some repetitive sequences in two stingless bee species, Frieseomelitta trichocerata and Plebeia poecilochroa. The species exhibit the typical diploid chromosome number of each genera, 2n=30 for Frieseomelitta and 2n=34 for Plebeia. Additionally, some individuals of P. poecilochroa presented a small heterochromatic B chromosome, showing a numeric variation of n=17 to 18 in males and 2n=34 to 35 in females. In both species heterochromatin is primarily distributed in the short arm and centromeric regions. Centromeric regions were found to be AT-rich in both species, while subterminal/terminal regions of the short arms of one and six chromosomes presented GC-rich sites in P. poecilochroa and F. trichocerata, respectively. The rDNA clusters mapped on two chromosome pairs in F. trichocerata, and in only one in P. poecilochroa. Microsatellites (GA)n, (GAG)n, and (CAA)n were predominantly mapped in euchromatic regions, while the telomeric motif (TTAGG)n mapped to the ends of most chromosomes, including the B chromosome of P. poecilochroa. The other repetitive probes used, including the rDNA clusters, do not label the B chromosome of P. poecilochroa. Our cytogenetic data highlight both similarities and differences when compared to other congeneric species, expanding the chromosomal data for both genera.

Human Satellite 3 DNA encodes megabase-scale transcription factor binding platforms.

Eukaryotic genomes are frequently littered with large arrays of tandem repeats, called satellite DNA, which underlie the constitutive heterochromatin often found around centromeric regions. While some satellite DNA types have well-established roles in centromere biology, other abundant satellite DNAs have poorly characterized functions. For example, Human Satellite 3 (HSat3), which makes up roughly 2% of the human genome, forms enormous arrays up to tens of megabases, but these arrays play no known roles in centromere function and were almost fully excluded from genome assemblies until recently. As a result, these massive genomic regions have remained relatively understudied, and the potential functional roles of HSat3 have remained largely unknown. To address this, we performed a systematic screen for novel HSat3 binding factors. Our work revealed HSat3 arrays contain high densities of transcription factor (TF) motifs that are bound by factors related to multiple, highly conserved signaling pathways. Unexpectedly, the most enriched TFs in HSat3 belong to the Hippo pathway transcription effector family TEAD. We found that TEAD recruits the co-activator YAP to HSat3 regions in a cell-state specific manner. Using RNA polymerase-I reporter assays, targeted repression of HSat3, inducible degradation of YAP, and super-resolution microscopy, we show that HSat3 arrays can localize YAP/TEAD inside the nucleolus, where YAP regulates RNA Polymerase-I activity. Beyond revealing a direct relationship between the Hippo pathway and ribosomal DNA regulation, this work demonstrates that satellite DNA can encode multiple transcription factor binding motifs, defining a new role for these enormous genomic elements.

Effect of Gossypol on Gene Expression in Swine Granulosa Cells.

Gossypol (GP), a polyphenolic compound in cottonseed, has notable effects on female reproduction and the respiratory system in pigs. This study aimed to discern the alterations in gene expression within swine granulosa cells (GCs) when treated with two concentrations of GP (6.25 and 12.5 µM) for 72 h, in vitro. The analysis revealed significant changes in the expression of numerous genes in the GP-treated groups. A Gene Ontology analysis highlighted that the differentially expressed genes (DEGs) primarily pertained to processes such as the mitotic cell cycle, chromosome organization, centromeric region, and protein binding. Pathway analysis using the Kyoto Encyclopedia of Genes and Genomes (KEGG) indicated distinct impacts on various pathways in response to different GP concentrations. Specifically, in the GP6.25 group, pathways related to the cycle oocyte meiosis, progesterone-mediated oocyte maturation, and p53 signaling were prominently affected. Meanwhile, in the GP12.5 group, pathways associated with PI3K-Akt signaling, focal adhesion, HIF-1 signaling, cell cycle, and ECM-receptor interaction showed significant alterations. Notably, genes linked to female reproductive function (CDK1, CCNB1, CPEB1, MMP3), cellular component organization (BIRC5, CYP1A1, TGFB3, COL1A2), and oxidation-reduction processes (PRDX6, MGST1, SOD3) exhibited differential expression in GP-treated groups. These findings offer valuable insights into the changes in GC gene expression in pigs exposed to GP.

Investigation of Transcription Factor and Cytokine Gene Expression Levels in Helper T Cell Subsets Among Turkish Patients Diagnosed with ICF2 (Novel ZBTB24 gene Variant) and ICF3 (CDCA7 Variant) Syndrome.

Immunodeficiency, centromeric region instability, facial anomalies syndrome (ICF), is a rare disease with autosomal recessive inheritance. ICF syndrome. It has been reported that ICF syndrome is caused by mutations in the DNMT3B (ICF1), ZBTB24 (ICF2), CDCA7 (ICF3), and HELLS (ICF4) genes. As a result of literature research, there are no studies on transcription factor and cytokine expressions of helper T cell subsets in ICF syndrome. In the study; Th1 (TBET, STAT1, STAT4), Th2 (GATA3, STAT6), Th17 (RORgt, STAT3), Treg (FoxP3, STAT5) transcription factors and the major cytokines of these cells (Th1; IFNG, Th2; IL4, Th17; IL17A-21-22, Treg; IL10, TGFβ) expressions were aimed to be evaluated by qRT-PCR. Patients (ICF3: three patients; ICF2: two patients), six heterozygous individual and five healthy controls were included in the study. All patients had hypogammaglobulinemia. Except for the CD19 cells of P2 from patients diagnosed with ICF3, the CD3, CD4, CD8, and CD19 cells in the other ICF3 patients were normal. However, the rates of these cells were low in patients with ICF2 syndrome. Factors belonging to patients' Th1, Th17 and Treg cells were significantly lower than the control. Additionally, novel mutation was detected in ZBTB24 gene (c.1121-2A > T). Our study is the first molecular study on Th cell subsets in patients with ICF syndrome and a new mutation that causes ICF2 syndrome has been identified.

Aurora B and Aurora C pools at two chromosomal regions collaboratively maintain chromosome alignment and prevent aneuploidy at the second meiotic division in mammalian oocytes.

Correct chromosome segregation is essential to preserve genetic integrity. The two protein kinases, Aurora B and its meiotic homolog Aurora C, regulate attachments between chromosomal kinetochores and microtubules, thereby contributing to the accuracy of the chromosome segregation process. Here we performed a detailed examination of the localization and activity of Aurora B/C kinases, their partner Incenp and the kinetochore target Hec1, during the second meiotic division in mouse oocytes. We found that a majority of Aurora B and C changed their localization from the outer kinetochore region of chromosomes at prometaphase II to an inner central region localized between sister centromeres at metaphase II. Depletion of the Aurora B/C pool at the inner central region using the haspin kinase inhibitor 5-iodotubercidin resulted in chromosome misalignments at the metaphase II stage. To further understand the role of the Aurora B/C pool at the central region, we examined the behaviour of single chromatids, that lack a central Aurora B/C pool but retain Aurora B/C at the outer kinetochores. We found that kinetochore-microtubule attachments at single chromatids were corrected at both prometaphase II and metaphase II stages, but that single chromatids compared to paired chromatids were more prone to misalignments following treatment of oocytes with the Aurora B/C inhibitory drugs AZD1152 and GSK1070916. We conclude that the Aurora B/C pool at the inner central region stabilizes chromosome alignment during metaphase II arrest, while Aurora B/C localized at the kinetochore assist in re-establishing chromosome positioning at the metaphase plate if alignment is lost. Collaboratively these two pools prevent missegregation and aneuploidy at the second meiotic division in mammalian oocytes.

Novel centromeric repetitive DNA elements reveal karyotype dynamics in polyploid sainfoin (Onobrychis viciifolia).

Polyploidy is a common feature in eukaryotes with one of paramount consequences leading to better environmental adaptation. Heterochromatin is often located at telomeres and centromeres and contains repetitive DNA sequences. Sainfoin (Onobrychis viciifolia) is an important perennial forage legume for sustainable agriculture. However, there are only a few studies on the sainfoin genome and chromosomes. In this study, novel tandem repetitive DNA sequences of the sainfoin genome (OnVi180, OnVi169, OnVi176 and OnVidimer) were characterized using bioinformatics, molecular and cytogenetic approaches. The OnVi180 and OnVi169 elements colocalized within functional centromeres. The OnVi176 and OnVidimer elements were localized in centromeric, subtelomeric and interstitial regions. We constructed a sainfoin karyotype that distinguishes the seven basic chromosome groups. Our study provides the first detailed description of heterochromatin and chromosome structure of sainfoin and proposes an origin of heterozygous ancestral genomes, possibly from the same ancestral diploid species, not necessarily from different species, or for chromosome rearrangements after polyploidy. Overall, we discuss our novel and complementary findings in a polyploid crop with unique and complex chromosomal features.

The breast cancer biomarkers associated with the development of the disease; an in-silico-based study

Introduction: Breast cancer (BC) is among the top causes of mortality among women worldwide. Identifying genes by differential expression associated with the development of the disease helps us to better understanding the molecular mechanisms of BC. Objectives: Our study used in-silico analysis to identify hub genes could trigger the development of BC. Materials and Methods: We identified GSE38959 and GSE45827 for differentially expressed genes (DEGs) in the Gene Expression Omnibus (GEO) database, with an adjusted P<0.05. In both sets, logFC ≥ 2 and logFC ≤ -2 were observed in the DEGs that express themselves within cases and normal BC samples. A comparison was then performed, detecting two common datasets of DEGs using the GEO2R tool. Pathways were elucidated using the Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology databases. Thereafter, protein-protein interactions (PPIs) were analyzed using Cytoscape and Gephi. Finally, a GEPIA analysis was conducted to validate the target genes. Results: Using the GEO, 322 common DEGs were identified and 65 hub genes as PPIs. The DEGs were enriched in functions associated with cell division, chromosomes, centromeric regions, microtubule binding, and the cell cycle based on the gene ontology (GO) and KEGG pathways analysis. The expression of 6 genes, CDK1, CCNB1, TOP2A, CXCL12, IGF1, and KIT, represented statistically significant values when the normal and tumor samples were compared via GEPIA analysis. Conclusion: This study introduced six genes (CDK1, CCNB1, TOP2A, CXCL12, IGF1, and KIT) with high expression significantly, which could act as a biomarker for BC development (P<0.05 for all genes). Further comprehensive experimental in vivo studies are needed to describe their role in BC.

A chromosome-level genome assembly of Drosophila madeirensis, a fruit fly species endemic to the island of Madeira.

Drosophila subobscura is distributed across Europe, the Near East, and the Americas, while its sister species, Drosophila madeirensis, is endemic to the island of Madeira in the Atlantic Ocean. D. subobscura is known for its strict light-dependence in mating and its unique courtship displays, including nuptial gift-giving. D. subobscura has also attracted the interest of researchers because of its abundant variations in chromosomal polymorphisms correlated to the latitude and season, which have been used as a tool to track global climate warming. Although D. madeirensis can be an important resource for understanding the evolutionary underpinning of these genetic characteristics of D. subobscura, little work has been done on the biology of this species. Here, we used a HiFi long-read sequencing data set to produce a de novo genome assembly for D. madeirensis. This assembly comprises a total of 111 contigs spanning 135.5 Mb and has an N50 of 24.2 Mb and a BUSCO completeness score of 98.6%. Each of the 6 chromosomes of D. madeirensis consisted of a single contig except for some centromeric regions. Breakpoints of the chromosomal inversions between D. subobscura and D. madeirensis were characterized using this genome assembly, updating some of the previously identified locations.

Chromosomal diversity in Crematogaster Lund, 1831 (Formicidae: Myrmicinae) from the Amazon rainforest.

Crematogaster Lund, 1831 is a speciose ant genus globally distributed and easily recognizable. Although biogeographical theories explain some variation among Neotropical Crematogaster, several taxonomical issues remain unresolved. While cytogenetic approaches can help to delimit species, cytogenetic data are only available for 18 taxa. In this study, classical and molecular cytogenetic analyses were performed on five Crematogaster species from the Brazilian Amazon to identify species-specific patterns. Two different cytotypes, both with 2n=22 chromosomes were observed in Crematogaster erecta Mayr, 1866, suggesting the presence of cryptic species, although with different karyotypic formulas. Crematogaster aff. erecta had 2n=28, while C. limata Smith, 1858, C. tenuicula Forel, 1904 and Crematogaster sp. had 2n = 38. The telomeric motif (TTAGG)n was found in all five species, and the (TCAGG)n motif was detected in the telomeres of C. limata. This peculiar motif was also detected in the centromeric regions of C. erecta cytotype I. The microsatellite (GA)n was dispersed in the chromosomes of all species studied which also had a single intrachromosomal rDNA site. The cytogenetic results revealed notable interspecific and intraspecific variation, which suggests different chromosomal rearrangements involved in the origin of these variations, also highlighting the taxonomic value of cytogenetic data on Crematogaster.

Telomere-to-telomere, gap-free assembly of the Rosa rugosa reference genome

Rosa, a genus esteemed worldwide for its ornamental plants, has encountered barriers in functional genomic studies and further genetic enhancement due to incomplete sequences and floating regions in previously sequenced genomes. Our groundbreaking study introduced a meticulously assembled, continuous, and fully bridged reference genome for Rosa rugosa, constructed through a sophisticated combination of PacBio High-Fidelity, ONT ultra-long reads, and Hi-C data. This robust assembly spanned 444.55 Mb and encompassed 34 109 protein-coding genes. We have uniquely assembled each chromosome into single, gap-free structures, successfully identifying all 14 telomeres and seven centromeres, a feat not achieved previously. The centromeric regions were distinguished by tandem repeats, primarily composed of centromere-specific 159-bp monomers, and a significant enrichment of ATHILA/Gypsy long terminal repeat retrotransposons in proximal regions. Our research highlighted recent tandem duplications as instrumental in bolstering R. rugosa's stress tolerance, environmental adaptability, and enhanced anthocyanin synthesis. Furthermore, our study ventured into uncharted territory by predicting transcription factors potentially regulating anthocyanin biosynthesis through the employment of gene co-expression networks, providing new avenues for research. This comprehensive reference genome not only serves as a cornerstone for in-depth exploration of genomic architecture and functionalities in R. rugosa but also acts as a catalyst for innovative breeding strategies and genetic refinement within the genus.

Satellitome Analysis of Adalia bipunctata (Coleoptera): Revealing Centromeric Turnover and Potential Chromosome Rearrangements in a Comparative Interspecific Study.

Eukaryotic genomes exhibit a dynamic interplay between single-copy sequences and repetitive DNA elements, with satellite DNA (satDNA) representing a substantial portion, mainly situated at telomeric and centromeric chromosomal regions. We utilized Illumina next-generation sequencing data from Adalia bipunctata to investigate its satellitome. Cytogenetic mapping via fluorescence in situ hybridization was performed for the most abundant satDNA families. In silico localization of satDNAs was carried out using the CHRISMAPP (Chromosome In Silico Mapping) pipeline on the high-fidelity chromosome-level assembly already available for this species, enabling a meticulous characterization and localization of multiple satDNA families. Additionally, we analyzed the conservation of the satellitome at an interspecific scale. Specifically, we employed the CHRISMAPP pipeline to map the satDNAs of A. bipunctata onto the genome of Adalia decempunctata, which has also been sequenced and assembled at the chromosome level. This analysis, along with the creation of a synteny map between the two species, suggests a rapid turnover of centromeric satDNA between these species and the potential occurrence of chromosomal rearrangements, despite the considerable conservation of their satellitomes. Specific satDNA families in the sex chromosomes of both species suggest a role in sex chromosome differentiation. Our interspecific comparative study can provide a significant advance in the understanding of the repeat genome organization and evolution in beetles.

CentIER: Accurate centromere identification for plant genomes

This paper introduces CentIER, the first bioinformatic tool designed to detect complete centromeric regions without additional wet experiments. The accuracy of CentIER was validated on diverse plant genomes such as Arabidopsis, rice, maize and mulberry, and the results show that CentIER can perform significantly more complete and accurate detection than the existing tool.

Chromosomal Characterization of Five Medicinally Significant Phyllanthus Species in Bangladesh by DNA Base-Specific Fluorochrome Banding Technique

ABSTRACT Five Phyllanthus species were characterized using a fluorochrome chromosome banding technique with CMA and DAPI. This genus displayed a range of somatic chromosomal counts, including 2n = 2x = 26 (diploid) in P. acidus, P. niruri, and P. reticulatus; 2n = 6x = 48 (hexaploid) in P. urinaria; and 2n = 10x = 100 (decaploid) in P. emblica (wild and cultivated varieties), which exhibited a multi-basic chromosome number. The centromeric and terminal regions of the chromosomes contained most of the CMA and DAPI bands, indicating that GC- and AT-rich repeats had accumulated in these locations. The diversity based on the heterochromatin distribution patterns made it possible to use the CMA and DAPI banding approaches to analyze and characterize these five Phyllanthus species.

Functional roles of the interaction of Moa1 with CENP-C and Rec8 in meiosis of Schizosaccharomyces pombe.

The localization of the meiotic specific regulatory molecule Moa1 to the centromere is regulated by the kinetochore protein CENP-C, and participates in the cohesion of sister chromatids in the centromere region mediated by the cohesin Rec8. To examine the interaction of these proteins, we analyzed the interactions between Moa1 and Rec8, CENP-C by yeast two-hybrid assays and identified several amino acid residues in Moa1 required for the interaction with CENP-C and Rec8. The results revealed that the interaction between Moa1 and CENP-C is crucial for the Moa1 to participate in the regulation of monopolar attachment of sister kinetochores. However, mutation at S143 and T150 of Moa1, which are required for interaction with Rec8 in the two-hybrid assay, did not show significant defects. Mutations in amino acid residues may not be sufficient to interfere with the interaction between Moa1 and Rec8 in vivo. Further research is needed to determine the interaction domain between Moa1 and Rec8. This study revealed specific amino acid sites at which Moa1 affects the meiotic homologous chromosome segregation, providing a deeper understanding of the mechanism of meiotic chromosome segregation.

The gap-free genome of Forsythia suspensa illuminates the intricate landscape of centromeres.

Forsythia suspensa, commonly known as weeping forsythia, holds significance in traditional medicine and horticulture. Despite its ecological and cultural importance, the existing reference genome presents challenges with duplications and gaps, hindering in-depth genomic analyses. Here, we present a Telomere-to-Telomere (T2T) assembly of the F. suspensa genome, integrating Oxford Nanopore Technologies (ONT) ultra-long, Hi-C datasets, and high-fidelity (HiFi) sequencing data. The T2T reference genome (Fsus-CHAU) consists of 14 chromosomes, totaling 688.79Mb, and encompasses 33 932 predicted protein-coding genes. Additionally, we characterize functional centromeres in the F. suspensa genome by developing a specific CENH3 antibody. We demonstrate that centromeric regions in F. suspensa exhibit a diverse array of satellites, showcasing distinctive types with unconventional lengths across various chromosomes. This discovery offers implications for the adaptability of CENH3 and the potential influence on centromere dynamics. Furthermore, after assessing the insertion time of full-length LTRs within centromeric regions, we found that they are older compared to those across the entire genome, contrasting with observations in other species where centromeric retrotransposons are typically young. We hypothesize that asexual reproduction may impact retrotransposon dynamics, influencing centromere evolution. In conclusion, our T2T assembly of the F. suspensa genome, accompanied by detailed genomic annotations and centromere analysis, significantly enhances F. suspensa potential as a subject of study in fields ranging from ecology and horticulture to traditional medicine.