Cytogenetic and Genome Research最新文献

{"title":"Genomic Imprinting: Insights into diverse epigenetic regulatory mechanisms.","authors":"Gaurav Kumar Pandey, Rajiva Raman","doi":"10.1159/000547555","DOIUrl":"https://doi.org/10.1159/000547555","url":null,"abstract":"<p><p>Genomic imprinting is a well-known phenomenon in which certain genes are expressed in a sex-of-the-parent-specific manner resulting in mono-allelic expression. Over the years the diversity of mechanisms observed in imprinted gene clusters has provided a valuable model system for exploring the complexities of epigenetics, which can be extended to other cellular and disease models. This review examines these different mechanisms throughout early embryonic development and offers insights into the interactions among key players such as DNA methylation, histone modifications, and non-coding RNAs, as well as their regulatory impact on gene expression.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-21"},"PeriodicalIF":1.7,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144689425","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meiotic Arrest and Synaptonemal Complex failure in Infertile Men with Y Chromosome Microdeletions.","authors":"Vyacheslav B Chernykh, Elizaveta E Bragina, Lyubov F Kurilo, Maria A Pankratenkova, Anna A Kashintsova, Mikhail Yu Gabliya, Igor V Vinogradov, Irina I Vityazeva, Sergey V Bogolyubov, Victor E Spangenberg, Oxana L Kolomiets","doi":"10.1159/000547448","DOIUrl":"https://doi.org/10.1159/000547448","url":null,"abstract":"<p><strong>Background: </strong>The Y chromosome microdeletions are common genetic cause of male infertility. Mechanisms of impaired spermatogenesis and meiosis, as well as phenotypic variability, have not been sufficiently studied.</p><p><strong>Objective: </strong>The paper provides of results of spermatogenesis and meiotic study based on the analysis of synaptonemal complex (SC) in the spermatocyte nuclei in infertile men with Y chromosome microdeletions.</p><p><strong>Materials and methods: </strong>The study group consisted of nine male patients 27-32 years old with primary infertility with non-obstructive azoospermia. The patients had a 46,XY karyotype, and complete (n=4) and partial AZFc (n=2) deletions, complete AZFb (n=2) and AZFb+c (n=1) deletions. Semen analysis was performed and assessed according to the WHO guidelines (WHO, 2010). The AZF deletions were detected by multiplex PCR, analyzing Y-specific loci in accordance with guidelines for molecular diagnosis of the Y chromosome microdeletions. Testicular biopsy was performed by with the TESE technique. Testicular tissue fragments were assessed under a light microscope for the presence of spermatocytes, spermatids, spermatozoa, atypical and degenerating cells in the suspension and analyzed by histopathology. Immunostaining was performed using antibodies to the SYCP3, γH2AFX, RAD51 and MLH1 proteins.</p><p><strong>Results: </strong>In 6 examined patients, spermatocytes were found at stages of prophase I: leptotene - 32.3 ± 39.4 (0-100) %, zygotene - 17.4 ± 20.1 (0-63.6) %, pachytene - 48.6 ± 38.2 (0-100) %, diplotene - 1.8 ± 2.2 (0-5.6) %. Percentage of germ cells at stages was very close between patients with AZFc deletions and AZFb/AZFb+c deletions. In patient with complete AZFb+c deletion meiotic arrest at the zygotene with atypical SCs and incomplete synapsis in all nuclei was found. Complete meiotic arrest at the early-mid-pachytene was characterized for complete AZFc and AZFb deletions. Azoospermic patients with partial AZFc (gr/gr) deletions had incomplete meiotic arrest at the mid-pachytene.</p><p><strong>Conclusion: </strong>Our own and literature data indicate more severe spermatogenesis and meiosis failures in patients with AZFb+c and AZFb deletions in compare to AZFc deletions. Meiotic arrest at the early-mid-pachytene was common, but some variability was found in the severity of spermatogenesis abnormalities in patients with complete AZFc deletions, that requires further research.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-25"},"PeriodicalIF":1.7,"publicationDate":"2025-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144689426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fork Stalling and Template Switching in a Complex der(6)dn with Duplication of 6q24.3qter and 6p25.3: A Case Report.","authors":"Thania Alejandra Aguayo-Orozco, Ma Guadalupe Domínguez-Quezada, Horacio Rivera, Luis E Figuera, Eduardo Esparza-García, Luis Ángel Núñez-García, Elvira Garza-González, Carlos Córdova-Fletes","doi":"10.1159/000547454","DOIUrl":"https://doi.org/10.1159/000547454","url":null,"abstract":"<p><strong>Introduction: </strong>Partial trisomy of the 6q24qter region is a rare chromosomal disorder characterized by variable clinical features and poorly understood mechanistic origins.</p><p><strong>Case presentation: </strong>We describe a de novo complex der(6) chromosome in a patient with features consistent with partial 6q trisomy syndrome, including congenital heart disease, growth restriction, developmental delay, and dysmorphic traits. Molecular Findings. Whole-genome sequencing (WGS) identified duplications of 1.5 Mb on 6p25.3 and 23.3 Mb on 6q24.3-qter. While the 6p duplication appears benign, the phenotype is likely driven by dosage-sensitive 6q genes (ARID1B, TAB2, QKI) and possible additive effects from other duplicated genes. No parental pericentric inversion was detected by classical or molecular cytogenetics, and WGS revealed no inversion-associated breakpoints. Instead, chimeric (q-/q+) and truncated reads at the 6q junction support a replication-based origin, such as reversed template switching. FISH confirmed direct insertion of the 6q segment into 6p25.3, without a del/dup pattern typical of inversion-derived recombinants. Notably, WGS detected no direct 6p-6q junction reads, but identified chimeric 6p-15q-6q reads with 2-bp microhomologies, suggesting that chromosome 15 transiently mediated the rearrangement. Interspersed telomeric sequences and flanking Alu elements were also found at both breakpoints.</p><p><strong>Conclusion: </strong>Altogether, these findings support a model in which replication fork stalling and template switching-potentially facilitated by telomere dynamics and repetitive elements-led to the formation of a recombinant-like der(6) chromosome. This case highlights the mechanistic complexity of structural rearrangements and the role of replication-based errors in shaping human genomic variation.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-14"},"PeriodicalIF":1.7,"publicationDate":"2025-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144658673","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meiotic segregation analysis in sperm of a pericentric inversion of chromosome 19 heterozygous carrier: assessment of recombination frequency and genetic risk.","authors":"Nadezda V Shilova, Zhanna G Markova, Darya A Yurchenko, Mariya M Antonova, Darya M Guseva, Mariya I Shtaut, Vyacheslav B Chernykh","doi":"10.1159/000547315","DOIUrl":"https://doi.org/10.1159/000547315","url":null,"abstract":"<p><strong>Introduction: </strong>Pericentric inversions (PEI) are rare intrachromosomal balanced structural abnormalities. To achieve complete synapsis and recombination during meiosis, the pairing of normal and inverted chromosomes requires the formation of an inversion loop. A crossover within this inversion loop leads to the production of two complementary recombinant chromosomes, which may contain both duplicated and deleted segments, including regions distal to the inversion. The clinical relevance of inverted chromosomes is significant, as they can result in the generation of recombinant gametes that may lead to early miscarriages, stillbirths, or congenital abnormalities in the progeny of carriers. The empirical frequencies of recombinant spermatozoa in men heterozygous for inv(19)(p13.3q12) were estimated. Additionally, the presence of the interchromosomal effects (ICE) on chromosomes 13, 18, 21, X, and Y was evaluated.</p><p><strong>Methods: </strong>Fluorescence in situ hybridization (FISH) was performed on sperm nuclei using DNA probes for the subtelomeric regions of the short (p-) and long (q-) arms of chromosome 19, the centromeric regions of chromosome18, X, and Y as well as DNA probes for the regions 13q14 and 21q22.</p><p><strong>Results: </strong>The inverted segment on chromosome 19 measures 31.5 Mb, which represents 53.3% of the total length of the affected chromosome. FISH analysis of 2,923 sperm nuclei revealed no detection of recombinant chromosomes. ICE on chromosomes 13, 18, 21, X, and Y were not observed.</p><p><strong>Conclusion: </strong>Empirical data have been obtained for the first time regarding the frequency of gametes containing recombinant chromosomes, as well as the absence of interchromosomal effects on chromosomes 13, 18, 21, X, and Y during the meiotic segregation of the pericentric inversion of chromosome 19, inv(19)(q13.3q12). It was demonstrated that the extremely low risk of recombinant chromosome formation, falling below the detectable threshold (with 95% confidence intervals), is associated with inv(19)(p13.3q12). We hypothesize that the meiotic behavior of pericentric inversions is influenced not only by the relative size of the inverted segment but also by the morphological characteristics of the affected chromosome. Further studies are needed to explore the factors that influence the meiotic behavior of pericentric inversions.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-16"},"PeriodicalIF":1.7,"publicationDate":"2025-07-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144636534","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Post-translational modifications of the Werner syndrome protein WRN.","authors":"Amrita Machwe, David K Orren","doi":"10.1159/000547163","DOIUrl":"https://doi.org/10.1159/000547163","url":null,"abstract":"<p><strong>Background: </strong>Werner syndrome has been an excellent model for the study of human aging, and how chromosomal instability is related to phenotypes of normal aging including cancer. George Martin devoted his life to the study of Werner syndrome and human aging, and this review is dedicated to his memory.</p><p><strong>Summary: </strong>In this review, we highlight the post-translational modifications of WRN, the protein whose function is lacking in individuals with Werner syndrome. WRN is subject to phosphorylation, acetylation, ubiquitination and SUMOylation.</p><p><strong>Key messages: </strong>These modifications of WRN control its localization and function in the response to replication fork stress and repair of double-strand breaks that are a consequence of this stress.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-10"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144552594","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Clustered structural variants involving PHEX at Xp22 in a female patient with X-linked hypophosphatemia.","authors":"Erika Uehara, Yasuhiro Naiki, Atsushi Hattori, Maki Fukami, Keiko Matsubara","doi":"10.1159/000547186","DOIUrl":"https://doi.org/10.1159/000547186","url":null,"abstract":"<p><strong>Introduction: </strong>X chromosomal structural changes involving PHEX result in X-linked hypophosphatemia (XLH). However, their underlying mechanisms were poorly determined. Moreover, X chromosome inactivation (XCI) statuses in female patients with XLH remain to be studied.</p><p><strong>Case presentation: </strong>We conducted systematic genomic analyses for a woman with XLH and detected a 3.2 Mb tandem duplication at Xp22.33, a 1.9 Mb tandem duplication at Xp22.31, and a 0.8 Mb deletion involving PHEX at Xp22.11 on the paternally derived chromosome. The fusion junctions contained templated insertions and short nucleotide additions indicative of non-homologous end joining (NHEJ) or alternative-NHEJ. The patient had random XCI.</p><p><strong>Conclusion: </strong>This study provides evidence that PHEX haploinsufficiency leads to typical XLH in women with random XCI and that a 5.9 Mb rearrangement on Xp22 permits random XCI. Our results, together with previous findings, imply that clustered structural changes due to NHEJ/alternative-NHEJ are a unique type of human genomic rearrangements.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-14"},"PeriodicalIF":1.7,"publicationDate":"2025-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144552593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Erratum.","authors":"","doi":"10.1159/000546684","DOIUrl":"https://doi.org/10.1159/000546684","url":null,"abstract":"","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"72"},"PeriodicalIF":1.7,"publicationDate":"2025-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144539509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Establishment of Cell Cultures from the Cavefish Astyanax mexicanus: A Resource for in vitro Studies of Supernumerary B Chromosome Biology.","authors":"João Pedro Silva Climaco, Cesar Martins, Adauto Lima Cardoso","doi":"10.1159/000546231","DOIUrl":"10.1159/000546231","url":null,"abstract":"<p><strong>Introduction: </strong>Supernumerary B chromosomes have been extensively investigated using diverse in vivo approaches, revealing insights into their origin, nature, evolutionary dynamics, maintenance mechanisms, and effects on their carriers. Despite its broad applicability across various biological research fields, in vitro cell culture remains underexplored as a tool for studying B chromosome biology, with studies limited to using cell cultures only as a source of chromosome preparations.</p><p><strong>Methods: </strong>In the present study, cell cultures of the fish Astyanax mexicanus were established, with (AMEcfB) and without (AMEcf) the B chromosome, using caudal fin tissue collected through nonlethal procedures. These cultures were compared in terms of cell proliferation and in response to environmental stress (pH and temperature) using the MTT and RT-qPCR assay.</p><p><strong>Results: </strong>The AMEcf and AMEcfB cell lines exhibited karyotypic stability and high proliferative potential, demonstrating their suitability for diverse scientific applications. The B chromosome, found exclusively in a subpopulation of AMEcfB cells, influenced cell physiology by affecting cell division dynamics. Experiments under extreme pH and temperature conditions revealed differences in cell viability and gene expression between the two lines, highlighting the role of the B chromosome in modulating environmental responses.</p><p><strong>Conclusion: </strong>These findings align with previous reports on the effects of B chromosomes in living organisms. Thus, the A. mexicanus cell cultures established here represent a promising resource for investigations into B chromosome biology, offering significant ethical, economic, and methodological advantages.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"59-69"},"PeriodicalIF":1.7,"publicationDate":"2025-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144301348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Localization of Ribosomal DNA-Associated Retrotransposons Refines the Heterochromatin Map of the X Chromosome in Drosophila melanogaster.","authors":"Tatyana D Kolesnikova, Olga V Veselova, Galina V Pokholkova, Veit Schubert, Mikhail S Klenov","doi":"10.1159/000546918","DOIUrl":"10.1159/000546918","url":null,"abstract":"<p><strong>Introduction: </strong>R1 and R2 retrotransposons specifically integrate into 28S rRNA genes, thereby disrupting many rDNA units within the nucleolar organizer region (NOR) of Drosophila. However, they also appear to play mutualistic roles, contributing to the maintenance of rDNA copy number and the regulation of nucleolar dominance. In addition to their presence in nucleolar rDNA, R1 elements are strongly enriched in the pericentromeric heterochromatin of the X chromosome, located distal to the NOR. This enrichment coincides with several enigmatic genetic phenomena - such as the ABO and cr phenotypes - whose molecular basis remains poorly understood. Notably, this region is one of the least characterized domains of the Drosophila melanogaster genome, lying outside the reference assembly and unresolved in metaphase chromosome preparations.</p><p><strong>Methods: </strong>We performed cytological mapping of R1 and R2 retrotransposons in D. melanogaster heterochromatin using polytene chromosomes from Rif11 mutant, which suppresses under-replication of all types of heterochromatic sequences. These were combined with classical eu-heterochromatic inversions of the X chromosome.</p><p><strong>Results and conclusion: </strong>We identified distinct clusters of both R1 and R2 elements within the X chromosome heterochromatin outside the NOR. R1 elements are highly enriched in the region between the heterochromatic Stellate (hSte) gene cluster and the NOR. This zone exhibits a unique response to Su(var)3-9 mutations, characterized by pronounced decondensation and the formation of a pseudo-puff. Proximal to the R1-enriched domain and adjacent to hSte cluster, we observed a region enriched in R2 elements. The edges of the NOR also show R2 enrichment, likely corresponding to intra-nucleolar domains that accumulate transcriptionally inactive rDNA units. In contrast, nucleolar R1 elements - which also mark inactive rDNA units - are more evenly distributed across the entire NOR. Based on these findings, we propose a refined cytological map of X chromosome heterochromatin in D. melanogaster.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-17"},"PeriodicalIF":1.7,"publicationDate":"2025-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144282833","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meiosis in Hybrids: Looking for the Order in Disorder.","authors":"Irina Bakloushinskaya, Sergey Matveevsky","doi":"10.1159/000546658","DOIUrl":"10.1159/000546658","url":null,"abstract":"<p><strong>Background: </strong>The study of gametogenesis in hybrids between intraspecific chromosomal forms or distinct species is mainly aimed at identifying the successful outcome of the process to produce balanced, viable gametes. At the same time, deviations from typical meiotic progression patterns may provide a pivotal mechanism for speciation.</p><p><strong>Summary: </strong>The long history of studying the process of gametogenesis and the development of methodological approaches have helped clarify the cytological and molecular processes that occur during meiosis. Since the early 1980s, Prof. Oxana Kolomiets has been studying meiosis in various species, including mole voles Ellobius, with a focus on chromosome synapsis and other key events during prophase I. Research on hybrids from different chromosomal forms of mole voles has uncovered notable differences in how meiosis progresses and its impact on fertility. In cases where Robertsonian translocations exhibit incomplete homology, various chromosomal multivalents form during prophase I. These configurations are often so complex that the chance of producing balanced gametes appears minimal. Moreover, there were also variations in the formation of trivalents. These discrepancies are thought to arise due to the involvement of distinct chromosomes in Robertsonian translocations, which lead to alterations in the spatial structure of the nucleus. Autosomes and sex chromosomes can exhibit disparities in trajectories of movement, synapsis, and recombination in meiosis. These disparities manifest most distinctly in hybrids, where atypical interchromosomal interactions, including those between sex chromosomes and autosomes, occur. Such interactions are absent in normal meiocytes, highlighting the altered meiotic processes in hybrids.</p><p><strong>Key messages: </strong>Chromosomal rearrangements, such as Robertsonian translocations, neocentromeres, and dicentric chromosomes, alter nuclear architecture, leading to meiotic irregularities that disrupt the progression of meiosis and gametogenesis. Meiotic irregularities cause variation in hybrid fertility. The analysis of meiosis I prophase turns out to be highly efficient for understanding the mechanisms of speciation.</p>","PeriodicalId":11206,"journal":{"name":"Cytogenetic and Genome Research","volume":" ","pages":"1-17"},"PeriodicalIF":1.7,"publicationDate":"2025-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144198462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"生物学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}