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Cancer Genetics Jun 2024Germline heterozygous TP53 pathogenic variants (PVs) cause Li Fraumeni Syndrome (LFS, OMIM#151623). TP53 PVs at lower-than-expected variant allele frequencies (VAF) may...
BACKGROUND
Germline heterozygous TP53 pathogenic variants (PVs) cause Li Fraumeni Syndrome (LFS, OMIM#151623). TP53 PVs at lower-than-expected variant allele frequencies (VAF) may reflect postzygotic mosaicism (PZM) or clonal hematopoiesis (CH); however, no guidelines exist for workup and clinical management.
PATIENTS AND METHODS
Retrospective analysis of probands who presented to an academic cancer genetics program with a TP53 PV result on germline genetic testing.
RESULTS
Twenty-one of 125 unrelated probands (17 %) were found to harbor a TP53 PV with VAF<30 % or a designation of "mosaic". A diagnosis of PZM was made in nine (43 %) due to a clinical phenotype consistent with LFS with (n = 8) or without (n = 1) positive ancillary tissue testing. Twelve patients (57 %) were diagnosed with presumed CH (pCH) due to a diagnosis of a myeloproliferative neoplasm, negative ancillary tissue testing, clinical phenotype not meeting LFS criteria, no cancer, and/or no first cancer age<50. Of the 19 patients with biological offspring, nine had either partial or complete offspring testing, all negative.
CONCLUSIONS
Determining the etiology of low VAF TP53 PVs requires ancillary tissue testing and incorporation of clinical phenotype. Discerning PZM versus CH is important to provide optimal care and follow-up.
Topics: Humans; Genetic Testing; Tumor Suppressor Protein p53; Female; Mosaicism; Germ-Line Mutation; Male; Li-Fraumeni Syndrome; Retrospective Studies; Adult; Middle Aged; Young Adult; Adolescent
PubMed: 38677009
DOI: 10.1016/j.cancergen.2024.04.002 -
Genes Apr 2024Haploinsufficiency of the gene is implicated in a human neuro-ocular syndrome. Although identified as a nuclear protein highly expressed in the embryonic mouse brain,...
Haploinsufficiency of the gene is implicated in a human neuro-ocular syndrome. Although identified as a nuclear protein highly expressed in the embryonic mouse brain, molecular function remains elusive. This study explores the spatio-temporal expression of zebrafish co-orthologs, and , as a first step to elucidate their function. In silico analysis reveals high evolutionary conservation in the DNA-interacting domains for both orthologs, with significant syntenic conservation observed for the locus. In situ hybridization and RT-qPCR analyses on zebrafish embryos and larvae reveal distinct expression patterns: is expressed early in zygotic development, mainly in the central nervous system, while expression initiates during gastrulation, localizing later to dopaminergic telencephalic and diencephalic cell clusters. Both transcripts are enriched in the ganglion cell and inner neural layers of the 72 hpf retina, with widely distributed in the ciliary marginal zone. In the adult brain, and are found in the cerebellum, amygdala and ventral telencephalon, which represent the main areas affected in autistic patients. Overall, this study suggests 's potential involvement in eye and brain development, laying the groundwork for further investigations into -related neurobehavioral disorders.
Topics: Animals; Brain; Gene Expression Regulation, Developmental; Retina; Zebrafish; Zebrafish Proteins; Nerve Tissue Proteins; Membrane Proteins
PubMed: 38674426
DOI: 10.3390/genes15040492 -
Life (Basel, Switzerland) Apr 2024Commencing with sperm-egg fusion, the early stages of metazoan development include the cleavage and formation of blastula and gastrula. These early embryonic events play...
Commencing with sperm-egg fusion, the early stages of metazoan development include the cleavage and formation of blastula and gastrula. These early embryonic events play a crucial role in ontogeny and are accompanied by a dramatic remodeling of the gene network, particularly encompassing the maternal-to-zygotic transition. Nonetheless, the gene expression dynamics governing early embryogenesis remain unclear in most metazoan lineages. We conducted transcriptomic profiling on two types of gametes (oocytes and sperms) and early embryos (ranging from the four-cell to the gastrula stage) of an economically valuable flatfish-the Chinese tongue sole (Pleuronectiformes: Cynoglossidae). Comparative transcriptome analysis revealed that large-scale zygotic genome activation (ZGA) occurs in the blastula stage, aligning with previous findings in zebrafish. Through the comparison of the most abundant transcripts identified in each sample and the functional analysis of co-expression modules, we unveiled distinct functional enrichments across different gametes/developmental stages: actin- and immune-related functions in sperms; mitosis, transcription inhibition, and mitochondrial function in oocytes and in pre-ZGA embryos (four- to 1000-cell stage); and organ development in post-ZGA embryos (blastula and gastrula). These results provide insights into the intricate transcriptional regulation of early embryonic development in Cynoglossidae fish and expand our knowledge of developmental constraints in vertebrates.
PubMed: 38672775
DOI: 10.3390/life14040505 -
Biology Apr 2024Marine animals possess genomes of considerable complexity and heterozygosity. Their unique reproductive system, characterized by high fecundity and substantial early...
Marine animals possess genomes of considerable complexity and heterozygosity. Their unique reproductive system, characterized by high fecundity and substantial early mortality rates, increases the risk of inbreeding, potentially leading to severe inbreeding depression during various larval developmental stages. In this study, we established a set of inbred families of , with an inbreeding coefficient of 0.25, and investigated elimination patterns and the manifestations of inbreeding depression during major larval developmental stages. Reduced-representation genome sequencing was utilized to explore the genotype frequency characteristics across two typical elimination stages. The results revealed notable mortality in hatching and metamorphosis into mysis and post-larvae stages. Inbreeding depression was also evident during these developmental stages, with depression rates of 24.36%, 29.23%, and 45.28%. Segregation analysis of SNPs indicated an important role of gametic selection before hatching, accounting for 45.95% of deviation in the zoea stage. During the zygotic selection phase of larval development, homozygote deficiency and heterozygote excess were the main selection types. Summation of the two types explained 82.31% and 89.91% of zygotic selection in the mysis and post-larvae stage, respectively. The overall distortion ratio decreased from 22.37% to 12.86% in the late developmental stage. A total of 783 loci were identified through selective sweep analysis. We also found the types of distortion at the same locus could change after the post-larvae stage. The predominant shifts included a transition of gametic selection toward normal segregation and other forms of distortion to heterozygous excess. This may be attributed to high-intensity selection on deleterious alleles and genetic hitchhiking effects. Following larval elimination, a greater proportion of heterozygous individuals were preserved. We detected an increase in genetic diversity parameters such as expected heterozygosity, observed heterozygosity, and polymorphic information content in the post-larvae stage. These findings suggest the presence of numerous recessive deleterious alleles and their linkage and suggest a major role of the partial dominance hypothesis. The results provide valuable insights into the mechanisms of inbreeding depression in marine animals and offer guidance for formulating breeding strategies in shrimp populations.
PubMed: 38666880
DOI: 10.3390/biology13040268 -
Successful preimplantation genetic testing for fibrodysplasia ossificans progressiva: a case report.Journal of Medical Case Reports Apr 2024Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant condition that leads to significant disability and morbidity, characterised by the formation of...
PURPOSE OF THE STUDY
Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant condition that leads to significant disability and morbidity, characterised by the formation of heterotopic hard tissues within connective tissues. The condition has an incidence of approximately one per two million people worldwide. There is no known single effective treatment available for FOP. We report the world's first case of a healthy infant born following in vitro fertilisation (IVF) and preimplantation genetic testing for monogenic disorder (PGT-M) using Karyomapping for FOP.
CASE PRESENTATION
A 30-year-old Caucasian female with FOP presented with her partner seeking IVF with PGT-M to achieve a healthy pregnancy with an embryo unaffected by FOP.
METHODS
The couple underwent IVF and PGT-M using Karyomapping as the testing method. A multi-disciplinary team approach was utilised in planning this case, considering the additional risks of oocyte retrieval, pregnancy and childbirth in women with FOP.
MAIN FINDINGS
The oocyte retrieval was covered with a 5-day course of prednisolone to reduce the risk of a localised inflammatory reaction, which could result in subsequent heterotopic ossification. This was subsequently weaned down with reducing doses every two days. The patient underwent uncomplicated oocyte retrieval, yielding 12 mature oocytes. Following intracytoplasmic sperm injection (ICSI), ten zygotes having two pro-nuclei were cultured, and six underwent trophoectoderm biopsy and vitrification 5-6 days after retrieval. PGT-M via Karyomapping revealed four out of six (66.7%) of blastocysts were not carriers of the maternal high-risk FOP allele. In total, the patient had three separate embryo transfers. Pregnancy was achieved following the third frozen embryo transfer, which went to 37 weeks' gestation, and delivered by Caesarean section. The baby was born in excellent condition and is unaffected by FOP.
CONCLUSION
IVF/ICSI and PGT-M using Karyomapping was successfully implemented to identify embryos carrying the high-risk FOP allele resulting in a healthy livebirth.
Topics: Humans; Female; Myositis Ossificans; Preimplantation Diagnosis; Adult; Pregnancy; Fertilization in Vitro; Genetic Testing; Oocyte Retrieval; Infant, Newborn; Prednisolone; Karyotyping
PubMed: 38664849
DOI: 10.1186/s13256-024-04504-4 -
In Vitro Cellular & Developmental... Apr 2024The delivery of CRISPR/Cas ribonucleoprotein (RNP) complexes is gaining attention owing to its high cleavage efficiency and reduced off-target effects. Although RNPs can...
The delivery of CRISPR/Cas ribonucleoprotein (RNP) complexes is gaining attention owing to its high cleavage efficiency and reduced off-target effects. Although RNPs can be delivered into porcine zygotes via electroporation with relatively high efficiency, lipofection-mediated transfection appears to be versatile because of its ease of use, low cost, and adaptation to high-throughput systems. However, this system requires improvements in terms of embryo development and mutation rates. Therefore, this study elucidated the effects of culture methods and reagent combinations on the CRISPR/Cas9 gene editing systems by using three lipofection reagents: Lipofectamine™ CRISPRMAX™ Cas9 Transfection Reagent (CM), Lipofectamine™ 2000 Transfection Reagent (LP), and jetCRISPR™ RNP Transfection Reagent (Jet). Porcine zona pellucida-free zygotes were incubated for 5 h with Cas9, a guide RNA targeting CD163, and the above lipofection reagents. When examining the effect of culture methods using 4-well (multiple embryo culture) and 25-well plates (single embryo culture) on the efficiency of CM-mediated zygote transfection, the culture of embryos in 25-well plates significantly increased the blastocyst formation rate; however, there was no difference in mutation rates between the 4-well and 25-well plates. When assessing the effects of individual or combined reagents on the efficiency of zygote transfection, the mutation rate was significantly lower for individual LP compared to individual CM- and Jet-mediated transfections. Moreover, combinations of lipofection transfection reagents did not significantly increase the mutation rate or mutation efficiency.
PubMed: 38664280
DOI: 10.1007/s11626-024-00908-0 -
Journal of Applied Genetics Apr 2024Chromosomal rearrangements are often associated with playing a role in the speciation process. However, the underlying mechanism that favors the genetic isolation...
Comparative karyotype analysis of the red brocket deer (M. americana sensu lato and M. rufa) complex: evidence of drastic chromosomal evolution and implications on speciation process.
Chromosomal rearrangements are often associated with playing a role in the speciation process. However, the underlying mechanism that favors the genetic isolation associated with chromosomal changes remains elusive. In this sense, the genus Mazama is recognized by its high level of karyotype diversity among species with similar morphology. A cryptic species complex has been identified within the genus, with the red brocket deer (Mazama americana and Mazama rufa) being the most impressive example. The chromosome variation was clustered in cytotypes with diploid numbers ranging from 42 to 53 and was correlated with geographical location. We conducted an analysis of chromosome evolution of the red brocket deer complex using comparative chromosome painting and Bacterial Artificial Chromosome (BAC) clones among different cytotypes. The aim was to deepen our understanding of the karyotypic relationships within the red brocket, thereby elucidating the significant chromosome variation among closely related species. This underscores the significance of chromosome changes as a key evolutionary process shaping their genomes. The results revealed the presence of three distinct cytogenetic lineages characterized by significant karyotypic divergence, suggesting the existence of efficient post-zygotic barriers. Tandem fusions constitute the main mechanism driving karyotype evolution, following a few centric fusions, inversion X-autosomal fusions. The BAC mapping has improved our comprehension of the karyotypic relationships within the red brocket deer complex, prompting questions regarding the role of these changes in the speciation process. We propose the red brocket as a model group to investigate how chromosomal changes contribute to isolation and explore the implications of these changes in taxonomy and conservation.
PubMed: 38662189
DOI: 10.1007/s13353-024-00861-4 -
Frontiers in Plant Science 2024is a monotypic species of rare and tertiary relic trees mainly distributed in China. is a potentially valuable horticultural plant, which has significant ornamental...
is a monotypic species of rare and tertiary relic trees mainly distributed in China. is a potentially valuable horticultural plant, which has significant ornamental and research value, and is a crucial tool for the study of phylogeography. The artificial cultivation of is of great scientific value and practical significance. In this study, we developed a direct organogenesis process of using mature zygotic embryos as initial materials. The highest sterile germination induction (54.5%) from the mature zygotic embryo was obtained in a Murashige and Skoog (MS) medium with 2.0 mg·L 6-benzylaminopurine (6-BA) and 0.2 mg·L α-naphthaleneacetic acid (NAA). The highest percentage of shoot regeneration (90.37%) was attained using 1.0 mg·L 6-BA and 0.01 mg·L NAA in the MS medium. The Woody Plant Medium (WPM) had the greatest adventitious shoot elongation rate of 93.33%. The most optimized rooting rate was 88.89% in a half-strength MS medium containing 2.0 mg·L indole-3-butyric acid (IBA) and 1.0 mg·L NAA. The genetic fidelity of regenerated plantlets was assessed using inter-simple sequence repeats and random amplified polymorphic DNA molecular markers, confirming the genetic uniformity and stability of regenerated plantlets. Our research presents an effective propagation system for , laying the groundwork for its germplasm conservation and large-scale production while maintaining high genetic integrity.
PubMed: 38660444
DOI: 10.3389/fpls.2024.1259925 -
Stem Cells (Dayton, Ohio) Apr 2024Fully grown oocytes have the natural ability to transform two terminally differentiated gametes into a totipotent zygote representing acquisition of totipotency. This...
Fully grown oocytes have the natural ability to transform two terminally differentiated gametes into a totipotent zygote representing acquisition of totipotency. This process wholly depends on maternal-effect factors (MFs). MFs stored in the eggs are therefore likely to be able to induce cellular reprogramming to a totipotency state. Here we report the generation of totipotent-like stem cells from mESCs using 4MFs Hsf1, Zar1, Padi6 and Npm2, designated as MFiTLSCs. MFiTLSCs exhibited unique and inherent capability to differentiate into embryonic and extraembryonic derivatives. Transcriptomic analysis revealed that MFiTLSCs are enriched with 2-cell-specific genes that appear to synergistically induce a transcriptional repressive state, in that parental genomes are remodelled to a poised transcriptional repression state while totipotency is established following fertilization. This method to derive MFiTLSCs could help advance understanding of fate determinations of totipotent stem cells in a physiological context and establish a foundation for development of oocyte biology-based reprogramming technology.
PubMed: 38655883
DOI: 10.1093/stmcls/sxae029 -
Journal of Experimental Zoology. Part... Aug 2024Methylosome protein 50 (Mep50) is a protein that is rich in WD40 domains, which mediate and regulate a variety of physiological processes in organisms. Previous studies...
Methylosome protein 50 (Mep50) is a protein that is rich in WD40 domains, which mediate and regulate a variety of physiological processes in organisms. Previous studies indicated the necessity of Mep50 in embryogenesis in mice Mus musculus and fish. This study aimed to further understand the roles of maternal Mep50 in early embryogenesis using medaka Oryzias latipes as a model. Without maternal Mep50, medaka zygotes developed to the pre-early gastrula stage but died later. The transcriptome of the embryos at the pre-early gastrula stage was analyzed by RNA sequencing. The results indicated that 1572 genes were significantly upregulated and 741 genes were significantly downregulated in the embryos without maternal Mep50. In the differentially expressed genes (DEGs), the DNA-binding proteins, such as histones and members of the small chromosome maintenance complex, were enriched. The major interfered regulatory networks in the embryos losing maternal Mep50 included DNA replication and cell cycle regulation, AP-1 transcription factors such as Jun and Fos, the Wnt pathway, RNA processing, and the extracellular matrix. Quantitative RT-PCR verified 16 DEGs, including prmt5, H2A, cpsf, jun, mcm4, myc, p21, ccne2, cdk6, and col1, among others. It was speculated that the absence of maternal Mep50 could potentially lead to errors in DNA replication and cell cycle arrest, ultimately resulting in cell apoptosis. This eventually resulted in the failure of gastrulation and embryonic death. The results indicate the importance of maternal Mep50 in early embryonic development, particularly in medaka fish.
Topics: Animals; Oryzias; Embryonic Development; Gene Expression Regulation, Developmental; Fish Proteins; Embryo, Nonmammalian; Female
PubMed: 38654580
DOI: 10.1002/jez.2824