The Neotropical monophyletic catfish genus Harttia represents an excellent model to study karyotype and sex chromosome evolution in teleosts. Its species split into three phylogenetic clades distributed along the Brazilian territory and they differ widely in karyotype traits, including the presence of standard or multiple sex chromosome systems in some members. Here, we investigate the chromosomal rearrangements and associated synteny blocks involved in the origin of a multiple X1X2Y sex chromosome system present in three out of six sampled Amazonian-clade species. Using 5S and 18S ribosomal DNA fluorescence in situ hybridization and whole chromosome painting with probes corresponding to X1 and X2 chromosomes of X1X2Y system from H. punctata, we confirm previous assumptions that X1X2Y sex chromosome systems of H. punctata, H. duriventris and H. villasboas represent the same linkage groups which also form the putative XY sex chromosomes of H. rondoni. The shared homeology between X1X2Y sex chromosomes suggests they might have originated once in the common ancestor of these closely related species. A joint arrangement of mapped H. punctata X1 and X2 sex chromosomes in early diverging species of different Harttia clades suggests that the X1X2Y sex chromosome system may have formed through an X chromosome fission rather than previously proposed Y-autosome fusion.
- MeSH
- Y Chromosome MeSH
- Phylogeny MeSH
- In Situ Hybridization, Fluorescence MeSH
- Sex Chromosomes genetics MeSH
- Catfishes * genetics MeSH
- Animals MeSH
- Check Tag
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
Nuclear myosin 1 (NM1) has been implicated in key nuclear functions. Together with actin, it has been shown to initiate and regulate transcription, it is part of the chromatin remodeling complex B-WICH, and is responsible for rearrangements of chromosomal territories in response to external stimuli. Here we show that deletion of NM1 in mouse embryonic fibroblasts leads to chromatin and transcription dysregulation affecting the expression of DNA damage and cell cycle genes. NM1 KO cells exhibit increased DNA damage and changes in cell cycle progression, proliferation, and apoptosis, compatible with a phenotype resulting from impaired p53 signaling. We show that upon DNA damage, NM1 forms a complex with p53 and activates the expression of checkpoint regulator p21 (Cdkn1A) by PCAF and Set1 recruitment to its promoter for histone H3 acetylation and methylation. We propose a role for NM1 in the transcriptional response to DNA damage response and maintenance of genome stability.
- MeSH
- Apoptosis MeSH
- Cell Nucleus drug effects genetics metabolism pathology MeSH
- Cell Line MeSH
- Cell Cycle MeSH
- Epigenesis, Genetic MeSH
- Etoposide toxicity MeSH
- Transcription, Genetic * MeSH
- Histone-Lysine N-Methyltransferase genetics metabolism MeSH
- Cyclin-Dependent Kinase Inhibitor p21 genetics metabolism MeSH
- Myosin Type I genetics metabolism MeSH
- Mice MeSH
- Tumor Suppressor Protein p53 genetics metabolism MeSH
- DNA Damage * MeSH
- Cell Proliferation MeSH
- Chromatin Assembly and Disassembly * MeSH
- p300-CBP Transcription Factors genetics metabolism MeSH
- Animals MeSH
- Check Tag
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
During interphase, the chromosomes of eukaryotes decondense and they occupy distinct regions of the nucleus, called chromosome domains or chromosome territories (CTs). In plants, the Rabl's configuration, with telomeres at one pole of nucleus and centromeres at the other, appears to be common, at least in plants with large genomes. It is unclear whether individual chromosomes of plants adopt defined, genetically determined addresses within the nucleus, as is the case in mammals. In this study, the nuclear disposition of alien rye and barley chromosomes and chromosome arm introgressions into wheat while using 3D-FISH in various somatic tissues was analyzed. All of the introgressed chromosomes showed Rabl's orientation, but their relative positions in the nuclei were less clear. While in most cases pairs of introgressed chromosomes occupied discrete positions, their association (proximity) along their entire lengths was rare, and partial association only marginally more frequent. This arrangement is relatively stable in various tissues and during various stages of the cell cycle. On the other hand, the length of a chromosome arm appears to play a role in its positioning in a nucleus: shorter chromosomes or chromosome arms tend to be located closer to the centre of the nucleus, while longer arms are more often positioned at the nuclear periphery.
- MeSH
- Cell Nucleus MeSH
- Chromatin genetics MeSH
- Chromosomes, Plant * MeSH
- In Situ Hybridization, Fluorescence * methods MeSH
- Interphase * genetics MeSH
- Hordeum genetics MeSH
- Image Processing, Computer-Assisted MeSH
- Flow Cytometry MeSH
- Triticum genetics MeSH
- Secale genetics MeSH
- Publication type
- Journal Article MeSH
Paleogenomic and archaeological studies show that Neolithic lifeways spread from the Fertile Crescent into Europe around 9000 BCE, reaching northwestern Europe by 4000 BCE. Starting around 4500 BCE, a new phenomenon of constructing megalithic monuments, particularly for funerary practices, emerged along the Atlantic façade. While it has been suggested that the emergence of megaliths was associated with the territories of farming communities, the origin and social structure of the groups that erected them has remained largely unknown. We generated genome sequence data from human remains, corresponding to 24 individuals from five megalithic burial sites, encompassing the widespread tradition of megalithic construction in northern and western Europe, and analyzed our results in relation to the existing European paleogenomic data. The various individuals buried in megaliths show genetic affinities with local farming groups within their different chronological contexts. Individuals buried in megaliths display (past) admixture with local hunter-gatherers, similar to that seen in other Neolithic individuals in Europe. In relation to the tomb populations, we find significantly more males than females buried in the megaliths of the British Isles. The genetic data show close kin relationships among the individuals buried within the megaliths, and for the Irish megaliths, we found a kin relation between individuals buried in different megaliths. We also see paternal continuity through time, including the same Y-chromosome haplotypes reoccurring. These observations suggest that the investigated funerary monuments were associated with patrilineal kindred groups. Our genomic investigation provides insight into the people associated with this long-standing megalith funerary tradition, including their social dynamics.
- MeSH
- Archaeology * MeSH
- History, Ancient MeSH
- Genome, Human * MeSH
- Haplotypes * MeSH
- Humans MeSH
- Chromosomes, Human, Y genetics MeSH
- Burial MeSH
- Agriculture history MeSH
- Check Tag
- History, Ancient MeSH
- Humans MeSH
- Male MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Historical Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Geographicals
- United Kingdom MeSH
Loss of totipotentcy in an early embryo is directed by molecular processes responsible for cell fate decisions. Three dimensional genome organisation is an important factor linking chromatin architecture with stage specific gene expression patterns. Little is known about the role of chromosome organisation in gene expression regulation of lineage specific factors in mammalian embryos. Using bovine embryos as a model we have described these interactions at key developmental stages. Three bovine chromosomes (BTA) that differ in size, number of carried genes, and contain loci for key lineage regulators OCT4, NANOG and CDX2, were investigated. The results suggest that large chromosomes regardless of their gene density (BTA12 gene-poor, BTA5 gene-rich) do not significantly change their radial position within the nucleus. Gene loci however, may change its position within the chromosome territory (CT) and relocate its periphery, when stage specific process of gene activation is required. Trophectoderm specific CDX2 and epiblast precursor NANOG loci tend to locate on the surface or outside of the CTs, at stages related with their high expression. We postulate that the observed changes in CT shape reflect global alternations in gene expression related to differentiation.
- MeSH
- Cell Nucleus genetics MeSH
- Cell Lineage MeSH
- Embryonic Development MeSH
- In Situ Hybridization, Fluorescence MeSH
- Nanog Homeobox Protein genetics metabolism MeSH
- Octamer Transcription Factor-3 genetics metabolism MeSH
- Chromosomes, Mammalian genetics MeSH
- Cattle MeSH
- CDX2 Transcription Factor genetics metabolism MeSH
- Gene Expression Regulation, Developmental MeSH
- Animals MeSH
- Check Tag
- Cattle MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
OBJECTIVE: Infant and child mortality are some of the most substantial indicators of country welfare. Infant mortality (IM) in Latvia is constantly the highest among 25 Member States of the European Union. Since the regaining of independence in 1991, IM has decreased by almost 50%, however, it is still high enough to cause concern that the country will not be able to meet the UN Millennium Development Goals to decrease IM in Latvia by 2015. The Medical Faculty at the University of Latvia has conducted several studies identifying correlations between IM and GDP, total expenditure on health, unemployment and GINI coefficient. It is necessary to identify all IM causes and relationships which have not been studied, including the effect of social factors causing inequality between inhabitants of urban and rural areas: - The aim of the study was to determine the IM rate and the main death causes and their differences between rural and urban areas in Latvia (2000-2010). MATERIALS: This is a register-based study. The data of 1994 deceased infants was analyzed over the time period from 2000-2010. The studied population was divided into two groups - urban and rural areas by mothers' area of residence. Descriptive and analytical methods were used for analysis - frequency distribution, correlation and regression analysis. RESULTS: IM by maternal residence as well as IM indicators in the most common diagnostic subgroups have been higher in rural areas in the entire studied period (2000-2010). The decrease proportion of IM was more rapid in rural regions with a period average of 6.2% in comparison to urban regions - 2.6%. Annual decrease of IM from perinatal period conditions was 50% lower in rural than urban areas; annual decrease of IM from congenital malformations, deformations and chromosomal abnormalities was 20% lower in urban than rural areas; annual decrease in other diagnostic groups was 40% lower in urban than rural areas. During the study period, differences in infant mortality based on maternal socio- demographic factors, maternal health as well as pregnancy and obstetric history have been found, but the results of statistical analysis cannot be used to define these relationships as statistically significant in either areas. CONCLUSIONS: infant mortality in Latvia due to various conditions prevailing during perinatal period, external causes and sudden infant death syndrome can be substantially decreased - by improving the theoretical and technical capacity of obstetric departments in rural areas as well as educating society on preventable causes of death.
- MeSH
- Adult MeSH
- Infant MeSH
- Infant Mortality trends MeSH
- Humans MeSH
- Young Adult MeSH
- Infant, Newborn MeSH
- Registries MeSH
- Urban Health MeSH
- Rural Health MeSH
- Check Tag
- Adult MeSH
- Infant MeSH
- Humans MeSH
- Young Adult MeSH
- Infant, Newborn MeSH
- Female MeSH
- Publication type
- Journal Article MeSH
- Geographicals
- Europe MeSH
- Latvia MeSH
Chromosome painting (CP) refers to visualization of large chromosome regions, entire chromosome arms, or entire chromosomes via fluorescence in situ hybridization (FISH). For CP in plants, contigs of chromosome-specific bacterial artificial chromosomes (BAC) from the target species or from a closely related species (comparative chromosome painting, CCP) are typically applied as painting probes. Extended pachytene chromosomes provide the highest resolution of CP in plants. CP enables identification and tracing of particular chromosome regions and/or entire chromosomes throughout all meiotic stages as well as corresponding chromosome territories in premeiotic interphase nuclei. Meiotic pairing and structural chromosome rearrangements (typically inversions and translocations) can be identified by CP. Here, we describe step-by-step protocols of CP and CCP in plant species including chromosome preparation, BAC DNA labeling, and multicolor FISH.
The appearance of heterochromatin is generally accepted as a useful tool for the evaluation of the cell state including pathology; however, information on the heterochromatin DNA condensation state expressed by the image optical density in interphase nuclear regions and mitotic chromosomes with silent genes is very limited. Since human proliferating myeloblasts are a very convenient model, they were studied in the bone marrow of leukemic patients and established cell cultures using computer assisted image densitometry at the single cell level after heterochromatin visualization by a simple but sensitive cytochemical procedure for demonstration of DNA. As was expected, a high DNA image optical density was noted in central heterochromatin regions in contrast to the nuclear periphery at the nuclear envelope. Similarly, a high nuclear DNA image optical density was also expressed in mitotic chromosomes. Thus the possibility exists that the large heterochromatin DNA condensation expressed by the large image optical density in central nuclear regions, as in mitotic chromosomes, is related to silent gene locations. The similar width of mitotic chromosomes and chromatin fibrils in the heterochromatin regions in the interphase nuclei supports that explanation. The chromatin DNA fibrils in the central heterochromatin nuclear regions of interphase cells might just represent masked silent chromosomal segments. Such a conclusion is in harmony with “classical” cytology in the first part of the last century, which suggests the chromosome continuity from the mitotic division to the interphase where each chromatin region (“Kernbezirk”) actually represents a chromosomal territory.
- MeSH
- Staining and Labeling MeSH
- Chromatin genetics isolation & purification MeSH
- Chromosomes genetics MeSH
- DNA, Neoplasm genetics MeSH
- Financing, Organized MeSH
- Heterochromatin genetics isolation & purification MeSH
- Leukemia etiology genetics MeSH
- Humans MeSH
- Microscopy methods utilization MeSH
- Cell Line, Tumor MeSH
- Granulocyte Precursor Cells cytology immunology MeSH
- Cell Proliferation MeSH
- Cell Nucleus Structures genetics MeSH
- Check Tag
- Humans MeSH
Although it is well known that chromosomes are non-randomly organized during interphase, it is not completely clear whether higher-order chromatin structure is transmitted from mother to daughter cells. Therefore, we addressed the question of how chromatin is rearranged during interphase and whether heterochromatin pattern is transmitted after mitosis. We additionally tested the similarity of chromatin arrangement in sister interphase nuclei. We noticed a very active cell rotation during interphase, especially when histone hyperacetylation was induced or transcription was inhibited. This natural phenomenon can influence the analysis of nuclear arrangement. Using photoconversion of Dendra2-tagged core histone H4 we showed that the distribution of chromatin in daughter interphase nuclei differed from that in mother cells. Similarly, the nuclear distribution of heterochromatin protein 1β (HP1β) was not completely identical in mother and daughter cells. However, identity between mother and daughter cells was in many cases evidenced by nucleolar composition. Moreover, morphology of nucleoli, HP1β protein, Cajal bodies, chromosome territories, and gene transcripts were identical in sister cell nuclei. We conclude that the arrangement of interphase chromatin is not transmitted through mitosis, but the nuclear pattern is identical in naturally synchronized sister cells. It is also necessary to take into account the possibility that cell rotation and the degree of chromatin condensation during functionally specific cell cycle phases might influence our view of nuclear architecture.
- MeSH
- Cell Nucleolus drug effects genetics ultrastructure MeSH
- Cell Line MeSH
- Coiled Bodies drug effects genetics ultrastructure MeSH
- Chromosomal Proteins, Non-Histone genetics metabolism MeSH
- Dactinomycin pharmacology MeSH
- Fluorescent Dyes MeSH
- Microscopy, Fluorescence MeSH
- Photochemical Processes MeSH
- Heterochromatin drug effects genetics ultrastructure MeSH
- Histones genetics metabolism MeSH
- Histone Deacetylase Inhibitors pharmacology MeSH
- Protein Synthesis Inhibitors pharmacology MeSH
- Interphase drug effects genetics MeSH
- Hydroxamic Acids pharmacology MeSH
- Humans MeSH
- RNA, Messenger biosynthesis MeSH
- Mitosis drug effects genetics MeSH
- Mice MeSH
- Animals MeSH
- Check Tag
- Humans MeSH
- Mice MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
The radial position of a gene within its chromosome territory (CT) in the interphase nucleus is thought to depend on the transcriptional activity of the gene and on transcriptional activity, gene density, and conformation of the chromosomal surrounding. In this study we analyzed the position of the cell cycle regulator gene p21 within the CT of human chromosome 6 (HSA6) upon transcriptional activation. Whereas the majority of active p21 genes is located in the interior of the CT of HSA6, induction of p21 transcription correlates with increased variation of gene localization within the CT and with a higher percentage of p21 genes located at the periphery of the CT. Additionally it demonstrates once more that transcription can take place throughout CTs. Comparison of the p21 locus with two non-coding regions on HSA6 showed that both non-coding sequences are located more frequently in the interior of the CT than p21 genes although they are situated in chromosomal neighborhoods with widely differing gene density and regional transcriptional activity. Thus our data support models describing an influence of the transcriptional activity of a gene on the localization within its CT. However, our data also indicate that additional factors such as chromatin remodeling are implicated in the positioning of genes within the respective chromosome territory.
- MeSH
- Transcriptional Activation genetics physiology MeSH
- Chromosomes metabolism MeSH
- In Situ Hybridization, Fluorescence MeSH
- Cyclin-Dependent Kinase Inhibitor p21 genetics MeSH
- Humans MeSH
- Cell Line, Tumor MeSH
- Check Tag
- Humans MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
