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1.
Nature ; 631(8020): 378-385, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38961292

ABSTRACT

The execution of goal-oriented behaviours requires a spatially coherent alignment between sensory and motor maps. The current model for sensorimotor transformation in the superior colliculus relies on the topographic mapping of static spatial receptive fields onto movement endpoints1-6. Here, to experimentally assess the validity of this canonical static model of alignment, we dissected the visuo-motor network in the superior colliculus and performed in vivo intracellular and extracellular recordings across layers, in restrained and unrestrained conditions, to assess both the motor and the visual tuning of individual motor and premotor neurons. We found that collicular motor units have poorly defined visual static spatial receptive fields and respond instead to kinetic visual features, revealing the existence of a direct alignment in vectorial space between sensory and movement vectors, rather than between spatial receptive fields and movement endpoints as canonically hypothesized. We show that a neural network built according to these kinetic alignment principles is ideally placed to sustain ethological behaviours such as the rapid interception of moving and static targets. These findings reveal a novel dimension of the sensorimotor alignment process. By extending the alignment from the static to the kinetic domain this work provides a novel conceptual framework for understanding the nature of sensorimotor convergence and its relevance in guiding goal-directed behaviours.


Subject(s)
Models, Neurological , Movement , Superior Colliculi , Visual Perception , Animals , Female , Male , Goals , Kinetics , Motor Neurons/physiology , Movement/physiology , Nerve Net/cytology , Nerve Net/physiology , Photic Stimulation , Psychomotor Performance/physiology , Reproducibility of Results , Superior Colliculi/cytology , Superior Colliculi/physiology , Visual Perception/physiology
2.
Plant J ; 119(2): 1134-1157, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38709819

ABSTRACT

The evolutionary and ecological success of spermatophytes is intrinsically linked to the seed habit, which provides a protective environment for the initial development of the new generation. This environment includes an ephemeral nourishing tissue that supports embryo growth. In gymnosperms this tissue originates from the asexual proliferation of the maternal megagametophyte, while in angiosperms it is a product of fertilization, and is called the endosperm. The emergence of these nourishing tissues is of profound evolutionary value, and they are also food staples for most of the world's population. Here, using Orthofinder to infer orthologue genes among newly generated and previously published datasets, we provide a comparative transcriptomic analysis of seed nourishing tissues from species of several angiosperm clades, including those of early diverging lineages, as well as of one gymnosperm. Our results show that, although the structure and composition of seed nourishing tissues has seen significant divergence along evolution, there are signatures that are conserved throughout the phylogeny. Conversely, we identified processes that are specific to species within the clades studied, and thus illustrate their functional divergence. With this, we aimed to provide a foundation for future studies on the evolutionary history of seed nourishing structures, as well as a resource for gene discovery in future functional studies.


Subject(s)
Cycadopsida , Magnoliopsida , Phylogeny , Seeds , Transcriptome , Seeds/genetics , Seeds/metabolism , Magnoliopsida/genetics , Magnoliopsida/metabolism , Cycadopsida/genetics , Gene Expression Regulation, Plant , Endosperm/genetics , Endosperm/metabolism , Gene Expression Profiling , Biological Evolution
4.
Clin Transl Oncol ; 26(7): 1779-1789, 2024 Jul.
Article in English | MEDLINE | ID: mdl-38512450

ABSTRACT

OBJECTIVES: The S-REAL study aimed to assess the effectiveness of durvalumab as consolidation therapy after definitive chemoradiotherapy (CRT) in a real-world cohort of patients with locally advanced, unresectable stage III non-small cell lung cancer (LA-NSCLC) included in a Spanish early access program (EAP). METHODS: In this multicentre, observational, retrospective study we analysed data from patients treated in 39 Spanish hospitals, who started intravenous durvalumab (10 mg/kg every 2 weeks) between September 2017 and December 2018. The primary endpoint was progression-free survival (PFS). Secondary endpoints included patient characterization and adverse events of special interest (AESI). RESULTS: A total of 244 patients were followed up for a median of 21.9 months [range 1.2-34.7]. Median duration of durvalumab was 45.5 weeks (11.4 months) [0-145]. Median PFS was 16.7 months (95% CI 12.2-25). No remarkable differences in PFS were observed between patients with programmed cell death-ligand 1 (PD-L1) expression ≥ 1% or < 1% (16.7 versus 15.6 months, respectively). However, PFS was higher in patients who had received prior concurrent CRT (cCRT) versus sequential CRT (sCRT) (20.6 versus 9.4 months). AESIs leading to durvalumab discontinuation were registered in 11.1% of patients. CONCLUSIONS: These results are in line with prior published evidence and confirm the benefits of durvalumab in the treatment of LA-NSCLC patients in a real-world setting. We also observed a lower incidence of important treatment-associated toxicities, such as pneumonitis, compared with the pivotal phase III PACIFIC clinical study.


Subject(s)
Antibodies, Monoclonal , Carcinoma, Non-Small-Cell Lung , Chemoradiotherapy , Lung Neoplasms , Humans , Carcinoma, Non-Small-Cell Lung/therapy , Carcinoma, Non-Small-Cell Lung/pathology , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/mortality , Male , Female , Lung Neoplasms/therapy , Lung Neoplasms/pathology , Lung Neoplasms/drug therapy , Lung Neoplasms/mortality , Retrospective Studies , Aged , Middle Aged , Spain , Antibodies, Monoclonal/therapeutic use , Adult , Aged, 80 and over , Antineoplastic Agents, Immunological/therapeutic use , Neoplasm Staging , Progression-Free Survival , Consolidation Chemotherapy , B7-H1 Antigen/antagonists & inhibitors
6.
Elife ; 122023 Nov 03.
Article in English | MEDLINE | ID: mdl-37921437

ABSTRACT

Transsynaptic viral vectors provide means to gain genetic access to neurons based on synaptic connectivity and are essential tools for the dissection of neural circuit function. Among them, the retrograde monosynaptic ΔG-Rabies has been widely used in neuroscience research. A recently developed engineered version of the ΔG-Rabies, the non-toxic self-inactivating (SiR) virus, allows the long term genetic manipulation of neural circuits. However, the high mutational rate of the rabies virus poses a risk that mutations targeting the key genetic regulatory element in the SiR genome could emerge and revert it to a canonical ΔG-Rabies. Such revertant mutations have recently been identified in a SiR batch. To address the origin, incidence and relevance of these mutations, we investigated the genomic stability of SiR in vitro and in vivo. We found that "revertant" mutations are rare and accumulate only when SiR is extensively amplified in vitro, particularly in suboptimal production cell lines that have insufficient levels of TEV protease activity. Moreover, we confirmed that SiR-CRE, unlike canonical ΔG-Rab-CRE or revertant-SiR-CRE, is non-toxic and that revertant mutations do not emerge in vivo during long-term experiments.


Subject(s)
Rabies virus , Rabies , Humans , Rabies virus/genetics , Mutation , Cell Line , Genomic Instability
7.
Adv Ther ; 40(11): 5016-5036, 2023 11.
Article in English | MEDLINE | ID: mdl-37728696

ABSTRACT

INTRODUCTION: VEIN STEP was conducted to collect international data on the management of chronic venous disease (CVD) and to assess the effectiveness of conservative treatments for the relief of CVD signs and symptoms. METHODS: This international, observational, prospective, longitudinal, cohort study recruited adult outpatients consulting for symptomatic CVD. The primary objective was the effectiveness of conservative treatments on symptoms, signs and quality of life in a real-life setting assessed using a range of patient-reported outcome measures: 10-cm Visual Analog and Patient Global Impression of Change scales for symptoms; Venous Clinical Severity Score for physician assessment of signs; and 14-item ChronIc Venous Insufficiency Questionnaire (CIVIQ-14) for quality of life. At inclusion, patients were prescribed conservative treatment according to the physicians' usual practice. Follow-up visits took place at weeks 2 and 4, with an optional week 8 visit. RESULTS: The analysis set comprised 6084 subjects (78% female) from nine countries with a mean age of 50.6 ± 13.8 years and BMI of 28.0 ± 4.9 kg/m2. The most common CEAP classifications were C1 (23.0%), C2 (31.6%), and C3 (30.7%). Conservative therapy consisted of oral venoactive drugs (VADs; 95.8% of subjects) including micronized purified flavonoid fraction (MPFF 75.5%) and diosmin (18.8%), compression (52.0%), and topicals (31.5%). Conservative therapy led to global symptom improvement in 89% of patients after 2 weeks and 96% at 4 weeks. Pain, leg heaviness, cramps, and sensation of swelling were improved in 82%, 71%, 45.5%, and 46% of patients, respectively. Conservative therapy was associated with a decrease over time in patient-assessed global symptom intensity: - 2.37 ± 1.73 (P < 0.001) and physician-assessed disease severity - 1.83 ± 2.82 (P < 0.001). Among the VADs, MPFF-based conservative therapy was associated with the greatest reduction in symptom and sign intensity. Improvements in CIVIQ-14 were observed with all treatments but were greatest for MPFF. CONCLUSION: In this prospective study conducted in the real-world setting, treatment with conservative therapy, in particular MPFF, was associated with meaningful improvements in the clinical signs and symptoms of disease as well as in quality of life in patients with CVD. TRIAL REGISTRATION: ClinicalTrials.gov identifier NCT04574375.


STUDY AIM: The VEIN STEP study aimed to gather global data on managing chronic venous disease (CVD) and evaluate the usefulness of conservative (non-surgical) treatments for improving CVD signs and symptoms. METHODS: Persons included in the study group had symptomatic CVD and were visiting outpatient clinics. The main aim was to measure how well treatments improved symptoms, physical signs of the illness, and quality of life. Different methods were used to measure these aspects, such as rating symptoms on a 10-point scale and using questionnaires completed by patients and doctors. STUDY FINDINGS: 6084 participants from nine countries joined the study. They were mostly women (78%) with an average age of around 50. Common symptoms included leg pain and leg heaviness. Treatments consisted mainly of drugs active on vein function, like MPFF and diosmin, along with compression stockings and creams. Conservative treatment led to symptom improvement in 89% of patients after 2 weeks and 96% at 4 weeks. Pain and leg heaviness improved in most patients (82% and 71% over the same period) while cramps, and swelling showed improvement in 45.5% and 46% of patients, respectively. Patients reported a significant decrease in symptom intensity, and doctors observed a reduction in disease severity. MPFF was associated with the highest reduction in symptom intensity. Improvements in quality of life were observed with all treatments but were greatest for MPFF. CONCLUSION: The study highlights that conservative treatments, especially MPFF, are associated with significant improvements in the clinical signs and symptoms of patients with CVD as well as in their quality of life.


Subject(s)
Vascular Diseases , Venous Insufficiency , Adult , Female , Humans , Male , Middle Aged , Chronic Disease , Cohort Studies , Conservative Treatment , Prospective Studies , Quality of Life , Treatment Outcome , Vascular Diseases/drug therapy , Venous Insufficiency/drug therapy , Longitudinal Studies
8.
Front Bioinform ; 3: 1137815, 2023.
Article in English | MEDLINE | ID: mdl-37521316

ABSTRACT

One of the main topics of cardiovascular research is the study of calcium (Ca2+) handling, as even small changes in Ca2+ concentration can alter cell functionality (Bers, Annu Rev Physiol, 2014, 76, 107-127). Ionic calcium (Ca2+) plays the role of a second messenger in eukaryotic cells, associated with cellular functions such as cell cycle regulation, transport, motility, gene expression, and regulation. The use of fluorometric techniques in isolated cells loaded with Ca2+-sensitive fluorescent probes allows quantitative measurement of dynamic events occurring in living, functioning cells. The Cardiomyocytes Images Analyzer Python (CardIAP) application addresses the need to analyze and retrieve information from confocal microscopy images systematically, accurately, and rapidly. Here we present CardIAP, an open-source tool developed entirely in Python, freely available and useable in an interactive web application. In addition, CardIAP can be used as a standalone Python library and freely installed via PIP, making it easy to integrate into biomedical imaging pipelines. The images that can be generated in the study of the heart have the particularity of requiring both spatial and temporal analysis. CardIAP aims to open the field of cardiomyocytes and intact hearts image processing. The improvement in the extraction of information from the images will allow optimizing the usage of resources and animals. With CardIAP, users can run the analysis to both, the complete image, and portions of it in an easy way, and replicate it on a series of images. This analysis provides users with information on the spatial and temporal changes in calcium releases and characterizes them. The web application also allows users to extract calcium dynamics data in downloadable tables, simplifying the calculation of alternation and discordance indices and their classification. CardIAP aims to provide a tool that could assist biomedical researchers in studying the underlying mechanisms of anomalous calcium release phenomena.

9.
Database (Oxford) ; 20232023 05 10.
Article in English | MEDLINE | ID: mdl-37162753

ABSTRACT

Proteins are the structural, functional and evolutionary units of cells. On their surface, proteins are shaped into numerous depressions and protrusions that provide unique microenvironments for ligand binding and catalysis. The dynamics, size and chemical properties of these cavities are essential for a mechanistic understanding of protein function. Here, we present CaviDB, a novel database of cavities and their features in known protein structures. It integrates the results of commonly used cavity detection software with protein features derived from sequence, structural and functional analyses. Each protein in CaviDB is linked to its corresponding conformers, which also facilitates the study of conformational changes in cavities. Our initial release includes ∼927 773 distinct proteins, as well as the characterization of 36 136 869 cavities, of which 1 147 034 were predicted to be drug targets. The structural focus of CaviDB provides the ability to compare cavities and their properties from different conformational states of the protein. CaviDB not only aims to provide a comprehensive database that can be used for various aspects of drug design and discovery but also contributes to a better understanding of the fundamentals of protein structure-function relationships. With its unique approach, CaviDB represents an indispensable resource for the large community of bioinformaticians in particular and biologists in general. Database URL https://www.cavidb.org.


Subject(s)
Proteins , Software , Ligands , Proteins/chemistry , Protein Conformation , Protein Domains
10.
Nat Methods ; 20(4): 580-589, 2023 04.
Article in English | MEDLINE | ID: mdl-36864202

ABSTRACT

An exciting frontier in circuit neuroscience lies at the intersection between neural network mapping and single-cell genomics. Monosynaptic rabies viruses provide a promising platform for the merger of circuit mapping methods with -omics approaches. However, three key limitations have hindered the extraction of physiologically meaningful gene expression profiles from rabies-mapped circuits: inherent viral cytotoxicity, high viral immunogenicity and virus-induced alteration of cellular transcriptional regulation. These factors alter the transcriptional and translational profiles of infected neurons and their neighboring cells. To overcome these limitations we applied a self-inactivating genomic modification to the less immunogenic rabies strain, CVS-N2c, to generate a self-inactivating CVS-N2c rabies virus (SiR-N2c). SiR-N2c not only eliminates undesired cytotoxic effects but also substantially reduces gene expression alterations in infected neurons and dampens the recruitment of innate and acquired immune responses, thus enabling open-ended interventions on neural networks and their genetic characterization using single-cell genomic approaches.


Subject(s)
Rabies virus , Rabies , Humans , Rabies virus/genetics , Glycoproteins , Transcriptome , Antigens, Viral
13.
MethodsX ; 9: 101786, 2022.
Article in English | MEDLINE | ID: mdl-35910305

ABSTRACT

There are multiple tools for positive selection analysis, including vaccine design and detection of variants of circulating drug-resistant pathogens in population selection. However, applying these tools to analyze a large number of protein families or as part of a comprehensive phylogenomics pipeline could be challenging. Since many standard bioinformatics tools are only available as executables, integrating them into complex Bioinformatics pipelines may not be possible. We have developed OBI, an open-source tool aimed to facilitate positive selection analysis on a large scale. It can be used as a stand-alone command-line app that can be easily installed and used as a Conda package. Some advantages of using OBI are:•It speeds up the analysis by automating the entire process•It allows multiple starting points and customization for the analysis•It allows the retrieval and linkage of structural and evolutive data for a protein throughWe hope to provide with OBI a solution for reliably speeding up large-scale protein evolutionary and structural analysis.

14.
Transl Lung Cancer Res ; 11(7): 1497-1502, 2022 Jul.
Article in English | MEDLINE | ID: mdl-35958343

ABSTRACT

Paraneoplastic cerebellar degeneration (PCD) is one of the most prevalent neurological paraneoplastic syndromes, typically associated with small cell lung cancer (SCLC). PCD is thought to be caused by proteins expressed by tumor cells which trigger an antibody-mediated immune response. Despite PCD being commonly associated with anti-Yo, anti-Hu and anti-Tr/DNER antibodies, PCD is the most prevalent paraneoplastic syndrome in patients harboring anti-Zic4 antibodies. We report what, to our knowledge, is the first known case of anti-Zic4 mediated PCD in a patient with EGFR-mutated metastatic non-small cell lung cancer (NSCLC). Our patient was in complete response (CR) to targeted therapy and presented to the emergency room with drowsiness, unsteady gait and memory lapses. The diagnostic work-up revealed a diffuse cerebellar atrophy in the MRI, ruling out brain metastasis and leptomeningeal carcinomatosis. A body-CT scan showed no signs of recurrent disease. The cerebrospinal fluid (CSF) was within normal parameters. An onconeural antibody panel was conducted in a peripheral blood sample, detecting high levels of anti-Zic4 antibody by indirect immunofluorescence (IFI), results later confirmed by immunoblot testing. With the suspected diagnosis of an anti-Zic4 PCD, the case was discussed with the neurology department and treatment with high dose methylprednisolone was initiated. Considering the lack of substantial clinical benefit, the patient was then treated with intravenous immunoglobulins (IVIG) for 5 days, showing modest improvement. At this time, the patient presented minor disease relapse in the form of a sub-centimetric pulmonary nodule. Despite one cycle of chemotherapy, the patient's neurological condition deteriorated leading to fatal pneumonia secondary to progressive dysphagia. There is scarce evidence of paraneoplastic syndromes in EGFR-mutated NSCLC. Further research is warranted to stablish a possible association between anti-Zic4 and the EGFR molecular pathway.

15.
J Clin Med ; 11(11)2022 Jun 06.
Article in English | MEDLINE | ID: mdl-35683629

ABSTRACT

Immune checkpoint inhibitors (ICIs) have revolutionized the treatment landscape of non-small cell lung cancer (NSCLC), either used in monotherapy or in combination with chemotherapy. While some patients achieve durable responses, some will not get benefit from this treatment. Early identification of non- responder patients could avoid unnecessary treatment, potentially serious immune-related adverse events and reduce treatment costs. PD-L1 expression using immunohistochemistry is the only approved biomarker for the selection of patients that can benefit from immunotherapy. However, application of PD-L1 as a biomarker of treatment efficacy shows many deficiencies probably due to the complexity of the tumor microenvironment and the technical limitations of the samples. Thus, there is an urgent need to find other biomarkers, ideally blood biomarkers to help us to identify different subgroups of patients in a minimal invasive way. In this review, we summarize the emerging blood-based markers that could help to predict the response to ICIs in NSCLC.

16.
Bioinformatics ; 38(10): 2742-2748, 2022 05 13.
Article in English | MEDLINE | ID: mdl-35561203

ABSTRACT

MOTIVATION: After the outstanding breakthrough of AlphaFold in predicting protein 3D models, new questions appeared and remain unanswered. The ensemble nature of proteins, for example, challenges the structural prediction methods because the models should represent a set of conformers instead of single structures. The evolutionary and structural features captured by effective deep learning techniques may unveil the information to generate several diverse conformations from a single sequence. Here, we address the performance of AlphaFold2 predictions obtained through ColabFold under this ensemble paradigm. RESULTS: Using a curated collection of apo-holo pairs of conformers, we found that AlphaFold2 predicts the holo form of a protein in ∼70% of the cases, being unable to reproduce the observed conformational diversity with the same error for both conformers. More importantly, we found that AlphaFold2's performance worsens with the increasing conformational diversity of the studied protein. This impairment is related to the heterogeneity in the degree of conformational diversity found between different members of the homologous family of the protein under study. Finally, we found that main-chain flexibility associated with apo-holo pairs of conformers negatively correlates with the predicted local model quality score plDDT, indicating that plDDT values in a single 3D model could be used to infer local conformational changes linked to ligand binding transitions. AVAILABILITY AND IMPLEMENTATION: Data and code used in this manuscript are publicly available at https://gitlab.com/sbgunq/publications/af2confdiv-oct2021. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.


Subject(s)
Proteins , Protein Binding , Protein Conformation , Proteins/chemistry
17.
World J Clin Oncol ; 13(4): 276-286, 2022 Apr 24.
Article in English | MEDLINE | ID: mdl-35582653

ABSTRACT

The 2004 discovery of EGFR mutations, followed by ALK rearrangements, ushered in a targeted therapy era for advanced non-small cell lung cancer (NSCLC). Tyrosine kinase inhibitors targeting gene alterations have substantially improved survival and quality of life for patients with NSCLC. In the last decade, rearrangements of the ROS1 oncogene have been incorporated into healthcare practice that are applicable to another small subgroup of patients who benefit from similar targeted strategies. Recent genome studies of lung adenocarcinoma have identified other possible therapeutic targets, including RET, NTRK fusions, c-MET alterations, and activating mutations in KRAS, BRAF, and HER2, all with frequencies greater than 1%. Lung cancers harbouring these genome changes can potentially be treated with agents approved for other indications or under clinical development. This review updates the therapeutic arsenal that especially targets those genes.

18.
Polymers (Basel) ; 14(4)2022 Feb 15.
Article in English | MEDLINE | ID: mdl-35215661

ABSTRACT

Agroindustrial wastes are a cheap and abundant source of natural fibers and macromolecules that can be used in the manufacturing of biocomposites. This study presents the development and thermo-mechanical characterization of a bio-composite film (TPF/PF), made of thermoplastic banana flour (TPF) matrix and plantain fibers (PF). Fabricated materials were characterized by physical analysis, chemical composition, Fourier-transformed spectroscopy (FTIR), thermal analysis (TGA), mechanical analysis, and scanning electronic microscopy (SEM). The physical analysis showed that TPF and PF have a low density and high affinity to water resulting in a lightweight, renewable, and biodegradable TPF/PF composite. The chemical composition and spectra analysis of the fiber showed that PF is a potential candidate for reinforcing composites due to its high α-cellulose and low lignin content. The thermal analysis determined that TPF degrades at a lower temperature than PF, therefore the matrix sets the processing temperature for TPF/PF composite films. The mechanical test showed an improvement in the tensile properties of the composite in comparison to neat TPF. Tensile strength and Young's modulus were improved by 345% and 1196%, respectively, when PF fibers was used. Good bonding and mechanical interlocking of PF to the TPF were identified by SEM. Therefore, potential biocomposites can be developed using natural fibers and thermoplastic starches obtained from plantain agroindustrial wastes.

19.
Biochimie ; 197: 113-120, 2022 Jun.
Article in English | MEDLINE | ID: mdl-35183673

ABSTRACT

Promiscuous activities have been related to the capacity to catalyze reactions different from those a protein has evolved to sustain. In this work, we rethought the serum albumin's promiscuous behavior using evolutionary and structural analysis. We found that the cross aldol condensation of acetone and p-formylbenzonitrile is a promiscuous reaction conserved in humans serum albumin and in closely related albumins from other mammals. Evolutionary analysis indicates that the residues involved in this promiscuous reaction are evolving under positive selection, an evolutionary pattern indicating a putative functional adaptation. Also, key residues are located in an evolutionary conserved cavity connected with the protein surface with an also conserved tunnel and mutations involving these residues are described in human diseases. Overall, our results suggest that albumin could have evolved to sustain a still unknown biological function among the many others it maintains. Our results could contribute to better characterize the serum albumin family and raise questions about the evolution of protein promiscuity and function.


Subject(s)
Evolution, Molecular , Serum Albumin , Adaptation, Physiological , Animals , Catalysis , Humans , Mammals , Serum Albumin/genetics
20.
Genome Biol Evol ; 13(8)2021 08 03.
Article in English | MEDLINE | ID: mdl-34009298

ABSTRACT

Crosses between the wild tomato species Solanum peruvianum and Solanum chilense result in hybrid seed failure (HSF), characterized by endosperm misdevelopment and embryo arrest. We previously showed that genomic imprinting, the parent-of-origin-dependent expression of alleles, is perturbed in the hybrid endosperm, with many of the normally paternally expressed genes losing their imprinted status. Here, we report transcriptome-based analyses of gene and small RNA (sRNA) expression levels. We identified 2,295 genes and 387 sRNA clusters as differentially expressed when comparing reciprocal hybrid seed to seeds and endosperms from the two within-species crosses. Our analyses uncovered a pattern of overdominance in endosperm gene expression in both hybrid cross directions, in marked contrast to the patterns of sRNA expression in whole seeds. Intriguingly, patterns of increased gene expression resemble the previously reported increased maternal expression proportions in hybrid endosperms. We identified physical clusters of sRNAs; differentially expressed sRNAs exhibit reduced transcript abundance in hybrid seeds of both cross directions. Moreover, sRNAs map to genes coding for key proteins involved in epigenetic regulation of gene expression, suggesting a regulatory feedback mechanism. We describe examples of genes that appear to be targets of sRNA-mediated gene silencing; in these cases, reduced sRNA abundance is concomitant with increased gene expression in hybrid seeds. Our analyses also show that S. peruvianum dominance impacts gene and sRNA expression in hybrid seeds. Overall, our study indicates roles for sRNA-mediated epigenetic regulation in HSF between closely related wild tomato species.


Subject(s)
Solanum lycopersicum , Solanum , Endosperm/genetics , Endosperm/metabolism , Epigenesis, Genetic , Gene Expression Regulation, Plant , Genomic Imprinting , Solanum lycopersicum/genetics , RNA , Seeds/genetics , Solanum/genetics , Transcriptome
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