Biology subjects

Amarante, A. d. M.

Publications and source records attributed to Amarante, A. d. M..

4 recordsLinked to original sources

bioRxiv2026

m6A RNA methylation modulates Zika virus infection by regulating serine proteases in Aedes albopictus

Epitranscriptomic RNA modifications, particularly N6-methyladenosine (mA), have emerged as important regulators of host-virus interctions. However, the role of mA in arbovirus infection within mosquito vectors remains poorly defined. Here, we characterized the mA RNA methylation machinery in Aedes albopictus C6/36 cells and examined its contribution to Zika virus (ZIKV) replication. Arbovirus infection did not significantly alter the transcriptional levels or enzymatic activity of the core mA methyltransferase components METTL3 and METTL14. In contrast, pharmacological inhibition of METTL3 markedly enhanced ZIKV replication, indicating an antiviral role for mA in mosquito cells. Transcriptome-wide analysis of C6/36 cells treated with the METTL3 inhibitor STM2457 revealed extensive changes in gene expression, including the pronounced upregulation of multiple serine proteases, particularly members of the CLIP family. Single-nucleotide-resolution mapping of mA using GLORI-sequencing showed that m6A is absent from Zika virus RNA, but readily detectable in the A. albopictus transcriptome. Data analysis defined key features of the mosquito epitranscriptome and demonstrated that mA modifications are enriched within the coding regions of serine protease transcripts, supporting their direct regulation by mA. Functionally, inhibition of serine protease activity using AEBSF resulted in a significant reduction of ZIKV replication. Together, these findings identify mA RNA methylation as a critical regulator of ZIKV infection in mosquito cells and uncover an epitranscriptomic pathway linking mA-dependent control of serine proteases to vector-virus interactions. Author SummaryMosquito-borne viruses such as Zika virus pose a major threat to global public health. Successful transmission of these viruses depends not only on infection in humans, but also on their ability to replicate efficiently inside mosquito vectors. Chemical modifications of RNA, collectively known as epitranscriptomic marks, have recently emerged as important regulators of gene expression and virus-host interactions. Among these, N6-methyladenosine (m6A) is the most abundant internal RNA modification in eukaryotic cells. While m6A has been extensively studied in mammalian systems, its role in mosquito antiviral responses remains poorly understood. In this study, we investigated how m6A RNA methylation influences Zika virus infection in mosquito cells derived from Aedes albopictus. We found that reducing m6A levels enhances viral replication, indicating that this RNA modification restricts infection in mosquito cells. Notably, Zika virus RNA itself does not contain detectable m6A modifications. Instead, m6A regulates the expression of specific mosquito genes, including a group of serine proteases that influence viral replication. Pharmacological inhibition of these proteases significantly impaired virus growth, identifying them as key downstream effectors. Our findings reveal an antiviral role for m6A in mosquito cells and uncover a previously unrecognized epitranscriptomic pathway that shapes mosquito-virus interactions. Understanding how RNA modifications regulate arbovirus infection in vectors may open new avenues for strategies aimed at limiting virus transmission.

molecular biology↗

bioRxiv2025

Unravelling the role of epigenetic regulators during embryonic development of Rhipicephalus micropolus

Epigenetic modifications are long-lasting changes to the genome that influence a cells transcriptional potential, thereby altering its function. These modifications can trigger adaptive responses that impact protein expression and various cellular processes, including differentiation and growth. The primary epigenetic mechanisms identified to date include DNA and RNA methylation, histone modifications, and microRNA-mediated regulation of gene expression. The intricate crosstalk among these mechanisms makes epigenetics a compelling field for the development of novel control strategies, particularly through the use of epigenetic drugs targeting arthropod vectors such as ticks. In this study, we identified the Rhipicephalus microplus orthologs of canonical histone-modifying enzymes, along with components of the machinery responsible for m5C and 6mA-DNA, and m6A-RNA methylations. We further characterized their transcriptional profiles and enzymatic activities during embryonic development. To explore the functional consequences of epigenetic regulation in R. microplus, we evaluated the effects of various epigenetic inhibitors on the BME26 tick embryonic cell line. Molecular docking simulations were performed to predict the binding mode of these inhibitors to tick enzymes, followed by in vitro assessment of their effects on cell viability and morphology. Tick cells exposed to these inhibitors exhibited phenotypic and molecular alterations. Notably, we observed higher levels of DNA methylation in the mitochondrial genome compared to nuclear DNA. Inhibition of DNA methylation using 5-azacytidine (5-AZA) was associated with increased activity of the mitochondrial electron transport chain and ATP synthesis, but reduced cellular proliferation. Our findings highlight the importance of epigenetic regulation during tick embryogenesis and suggest that targeting these pathways may offer a novel and promising strategy for tick control. HighlightsO_LIR. microplus presents a complete set of epigenetic enzymes that modify histones, DNA and RNA C_LIO_LIEpigenetic regulation is highly dynamic, and functionally significant during R. microplus embryogenesis C_LIO_LIInhibition of DNA methylation leads to overactivation of the mitochondrial electron transport chain C_LI

molecular biology↗

bioRxiv2024

Analysis of gene expression in Aedes aegyptisuggests changes in early genetic control of mosquito development

Aedes aegypti, a critical vector for tropical diseases, poses significant challenges for studying its embryogenesis due to difficulties in removing its rigid chorion and achieving effective fixation for in situ hybridization. Here, we present novel methodologies for fixation, dechorionation, DAPI staining, and in situ hybridization, enabling the detailed analysis of gene expression throughout Ae. aegypti embryogenesis. By synchronizing eggs at various developmental stages (0-72 h), we localized the transcripts of the gap gene mille-pattes (mlpt), the dorsoventral gene cactus (cact), and the pioneer transcription factor (pTF) zelda (zld). In situ hybridization and RT-qPCR analyses revealed that mlpt and cact are maternally expressed, while zld expression begins zygotically during cellularization and later becomes prominent in neuroblasts. Analysis of previously published transcriptomes suggests that three other pTFs, CLAMP, grainyhead and GAF, are also maternally expressed and may function as pioneer transcription factors during Ae. aegypti embryogenesis. These findings suggest that the transcription factors responsible for genome activation in mosquitoes differ from those in fruit flies, highlighting significant divergence in the genetic regulation of early Dipteran embryogenesis.

developmental biology↗

bioRxiv2021

Zika virus infection drives epigenetic modulation of immunity by the histone acetyltransferase CBP of Aedes aegypti

Epigenetic mechanisms are responsible for a wide range of biological phenomena in insects, controlling embryonic development, growth, aging and nutrition. Despite this, the role of epigenetics in shaping insect-pathogen interactions has received little attention. Gene expression in eukaryotes is regulated by histone acetylation/deacetylation, an epigenetic process mediated by histone acetyltransferases (HATs) and histone deacetylases (HDACs). In this study, we explored the role of the Aedes aegypti histone acetyltransferase CBP (AaCBP) after infection with Zika virus (ZIKV), focusing on the two main immune tissues, the midgut and fat body. We showed that the expression and activity of AaCBP could be positively modulated by blood meal and ZIKV infection. Nevertheless, Zika-infected mosquitoes that were silenced for AaCBP revealed a significant reduction in the acetylation of H3K27 (CBP target marker), followed by downmodulation of the expression of immune genes, higher titers of ZIKV and lower survival rates. Importantly, in Zika-infected mosquitoes that were treated with sodium butyrate, a histone deacetylase inhibitor, their capacity to fight virus infection was rescued. Our data point to a direct correlation among histone hyperacetylation by AaCBP, upregulation of antimicrobial peptide genes and increased survival of Zika-infected-A. aegypti. Author summaryPathogens have coevolved with mosquitoes to optimize transmission to hosts. As natural vectors, mosquitoes are permissive to and allow systemic and persistent arbovirus infection, which intriguingly does not result in dramatic pathological sequelae that affect their lifespan. In this regard, mosquitoes have evolved mechanisms to tolerate persistent infection and develop efficient antiviral strategies to restrict viral replication to nonpathogenic levels. There is a great deal of evidence supporting the implication of epigenetics in the modulation of the biological interaction between hosts and pathogens. This study reveals that Zika virus infection positively modulates the expression and activity of A. aegypti histone acetyltransferase CBP (AaCBP). This study shows that AaCBP plays a role in the activation of immune-responsive genes to limit Zika virus replication. This first description that Zika virus infection has epigenomic consequences in the regulation of A. aegypti immunity opens a new avenue for research on mosquito factors that can drive vector competence.

molecular biology↗