La PF Transcriptome et Epigenome développe des projets de séquençage à haut débit (collaboration et service) avec des équipes du Campus. Ceux-ci couvrent l'ensemble des thématiques du campus ainsi qu'une large gamme d'organismes (des virus aux mammifères). La plate-forme exerce des activités de biologie humide (construction des librairies et séquençage) et de biologie sèche (analyse bioinformatiques et statistiques). La personne mise a disposition interagira étroitement avec les autres bioinformaticiens du pôle BioMics et du Hub. Ses activités concerneront notamment: - La participation à la conception et à la mise en place des projets avec les équipes demandeuses, la prise en charge des analyses et le reporting aux utilisateurs - La mise en place d'un workflow d'analyse bioinformatique des données de transcriptome /épigénome en étroite collaboration avec le C3BI, la DSI et les autres bioinformaticiens du pole. Ce workflow permettra le contrôle qualité des données, leur prétraitement, le mapping des séquences sur les génomes/transcriptomes de réference, et le comptage des reads pour les différents éléments de l'annotation - L'adaptation du workflow d'analyse aux questions biologiques et aux organismes étudiés dans le cadre des activités de la PF - L'activité de veille technologique et bibliographique (test et validation de nouveaux outils d'analyse, updates d'outils existants...) - La mise en place et le développement d'outils d'analyse adaptés aux futurs projets de la PF: single cell RNAseq, métatranscriptome, ChIPseq, analyse des isoformes de splicing.. Ceci se fera notamment via la réalisation d'analyses dédiées avec certains utilisateurs. Les outils mis en place et validés dans ce cadre seront ensuite utilisés pour l'ensemble des projets. - L'activité de communication et de formation (participation aux réunions du consortium France Génomique,formation permanente à l' Institut Pasteur… - la participation a d autres projets du Pole BioMics (selon disponibilité) Bernd Jagla, qui était le bioinformaticien de la plateforme a rejoint le Hub au 1er janvier 2016. Rachel Legendre est mise a disposition depuis le 2 novembre 2015 et remplace Bernd Jagla. Je souhaite que Rachel Legendre soit mise à disposition de la plateforme pour une durée d'au moins 2 ans.

We are comparing the bacterial communities of domestic and sylvatic  breeding sites and midguts of Aedes aegypti collected in Gabon.

Insect vectors durably transmit many important human and animal diseases. Insects are mobile, adaptable and difficult to control, which makes them efficient vehicles for disease emergence, spread and maintenance. Genomic tools have been applied to the study of vectors and vector control, and some insects such as the African malaria vector Anopheles gambiae have now become new model organisms for natural host-pathogen interactions. We study mosquito vectors of malaria and arboviruses, which generates four main kinds of large-scale data that requires dedicated bioinformatics expertise: i) functional dissection of mosquito immune signaling pathways by RNAseq transcriptome profiling to detect responses to pathogen infection and/or silencing of target genes, including mRNA as well as small and other non-coding RNAs, ii) next-gen genetic linkage mapping by deep sequencing of index-tagged phenotyped individual mosquitoes, iii) population genomic analysis by whole-genome sequencing of hundreds of individual 250Mb mosquito genomes, iv) metagenomic analysis of the mosquito microbiome and pathogen susceptibility, and of ecological metagenomic communities in field samples of mosquito vectors.

Anopheles mosquitoes are the vectors of Plasmodium parasites, the etiological agents of malaria in humans. In Anopheles gambiae, a major vector in Africa, parasite transmission is largely under genetic control. We have previously shown that a gene family is implicated in the immune control of the parasite in this vector. The response of the family members is pathogen-specific, with one controlling P. falciparum infection and the other controlling rodent parasites. Recently, the genome of Anopheles stephensi, the major Asian vector, has been sequenced and, in this species, there is only one gene. Knocking down this gene reduced lifespan of A. stephensi and antibiotic treatment restores a normal longevity, suggesting the implication of the gut microbiota. Therefore, we conducted a metagenomic analysis in order to identify the bacteria responsible for the shorten of the mosquito lifespan.

The genome of the yellow fever mosquito (Aedes Aegypti) is not fully annoyed, and this project aims at discovering novel transcripts using RNAseq data.

The goal of the project is to determine if there are differences in the midgut microbiome of our lab colonies of Aedes aegypti. We frequently observe various phenotypic differences between different colonies of mosquitoes and it is a recurring question whether these phenotypic differences are a result of differences in the microbiome. We will sequence the microbiome of 6 representative established lab colonies that have been collected from geographically diverse areas and compare the bacterial communities between the them. This data will help us dissect the importance that variation of the midgut microbiome of lab colonies of Aedes aegypti has on the phenotypic differences we observe in the lab.

Yellow fever virus (YFV), a Flavivirus transmitted by mosquitoes causes a severe hemorrhagic fever in humans. Despite the availability of a safe and effective vaccine (17D), YFV is still a public health problem in tropical Africa and South America. In the Americas, the massive campaign of mosquito control during the first half of the 20th century led to the eradication of Aedes aegypti from most American countries, and as a consequence, urban outbreaks of YF were no longer observed. However, the relaxation of vector control led to the reinfestation of urban areas by Ae. aegypti and the subsequent establishment of the Asian tiger mosquito Aedes albopictus. In Brazil, while human cases are sporadically detected in the Amazonian basin where sylvatic YFV strains circulate between non-human primates and arboreal canopy-dwelling mosquitoes (Haemagogus sp.), they are increasingly reported outside the jungle moving towards the Atlantic coast, the most populated area. In the absence of routine immunization programs, YF may come back in the American towns as it was in the past. The causes leading to the current YF resurgence are multifactorial. From a mosquito vector viewpoint, changes in vector densities, distribution, vector competence or vector as a site of selection for epidemic YFV strains, can be regarded as critical factors. Our project aims to address the contribution of the invasive mosquito Ae. albopictus as a missing link to allow a selvatic YF strain (1D) to become adapted for a transmission in urban areas by the human-biting mosquito, Ae. aegypti. It will be done through three specific objectives: (i) identify Ae. albopictus-adaptive mutations after serial cycling of the selvatic YFV-1D on Brazilian Ae. albopictus mosquitoes, (ii) evaluate their potential to be transmitted to a vertebrate host, and (iii) deepen the transmission of the experimentally selected viruses by field-collected mosquito populations.

In early development, regulation of transcription results in precisely positioned and highly reproducible expression patterns that specify cellular identities. How transcription, a fundamentally noisy molecular process, is regulated to achieve reliable embryonic patterning remains unclear. In particular, it is unknown how gene-specific regulation mechanisms affect kinetic rates of transcription, and whether there are common, global features that govern these rates across a genetic network. Quantitative measurements of nascent transcriptional activity in both living and fixed tissues are key in order to understand the underlying transcription kinetics and to make progress with these fundamental questions. The current project aims at constructing realistic minimalist models of transcription for different experimental and developmental contexts, using spatiotemporal gene expression activity data obtained from microscopic imaging of live biological tissues.

Aedes albopictus is an important vector for transmitting arboviruses, such as Dengue, Chikungunya, West Nile or Zika viruses. Its worldwide distribution due to its high ability to adapt to variable environments makes this species a serious threat. This mosquito also better transmits Chikungunya than Dengue virus, and many studies are still trying to understand the deep relationships between these viruses and their vectors in order to develop new control strategies. Moreover, it is now well known that retroviruses partially integrate into host's genomes since it is mandatory for their replication cycle. Interestingly, Retroviridae are not the only viral family capable of host integration. Indeed, in the last decade, owing to new molecular technologies such as next-generation sequencing and bioinformatic tools, non-retroviral integrated RNA virus sequences (NIRVS) have been found into many animal genomes, including Aedes mosquitoes. This came as a surprise since RNA viruses do not have DNA intermediate in their replication cycle. However, little is known about these integrations and many questions remained unsolved. The aim of this project is to assess the production of NIRVS in persistently-infected cells from Ae. albopictus and Ae. aegypti. It is divided in several critical points : the first one is to know how fast the virus can integrate into the cell genome. The second one is to determine which part of the viral genome can integrate and finally, where can it integrate in the genome. This will allow us to understand the virus/host interaction and if NIRVS formation is a mechanism that vectors/hosts evolved as a general response to RNA viruses.

As a result of combined climate change and globalization (increased flow of travelers and goods), the distribution of the mosquito Aedes albopictus is expanding significantly outside tropical regions. Ae. albopictus has already established stable colonies in 20 European countries (https://ecdc.europa.eu/en/publications-data/aedes-albopictus-current-known-distribution-june-2018). Being the main mosquito that can be incriminated in the transmission of chikungunya, dengue, and zika viruses in Europe, Ae. albopictus were responsible for the first autochthonous cases in France and Italy. Accordingly, the European countries that are infested with Ae. albopictus are under the risk of arboviral diseases outbreak. The vector competence analysis of European Ae. albopictus is pivotal for evaluating the potential risk of diseases transmission. In this study, we analyzed the viral susceptibility of several European Ae. albopictus populations from Croatia, Greece, Montenegro, Italy, Switzerland, and also China (as a control), for chikungunya, dengue, and zika viruses. The results indicated that the European Ae. albopictus were able to transmit chikungunya and dengue viruses whereas they were not an efficient vector for zika virus.

Despite the worldwide importance of malaria due to Plasmodium vivax, there is currently almost no data on the molecular responses of the Anopheles mosquito vectors to this parasite species. Understanding these responses will contribute to identify relevant strategies to interrupt the transmission of P. vivax by targeting the mosquito vector. Such approaches are urgently needed, as P. vivax is difficult to target on the long term in humans as a consequence of the hypnozoite stage that is responsible for relapses. This project will investigate the molecular response of Anopheles arabiensis, member of the Anopheles gambiae complex, to P. vivax from experimental infections performed in Madagascar where both mosquito and parasite are present. This is a unique situation that will capitalize on the strong knowledge and tools available for An. gambiae sensu lato. The response will be compared to the one triggered by P. falciparum, also present in Madagascar. From mosquitoes infected in a field setting, a transcriptomic (RNAseq) approach will be used to identify common and unique pathways to both parasite species. These analyses will further contribute to identify targets for interrupting transmission of each or both parasites simultaneously. However, a pilot study performed with the PF transcriptomics & epigenomics revealed that the current release of the An. arabiensis genome is poorly annotated. Therefore, to be able to make sens of the RNAseq analyses per se, a strong support from the C3BI Hub for bioinformatics and biostatistics is critical.

This project to characterize defective viral genomes of shrimp pathogens i.e. Yellow head virus (YHV) from next-generation sequencing of viral RNAs data by using DI-tector or similar tools. NGS data are already available for analysis. We are looking for someone interested in virology in general and more precisely the complexity of viral genomes.

Although the microbiota of mosquitoes is known to play an important role in their vectorial capacity for human pathogens, most earlier studies have focused on mosquito-bacteria interactions at the adult stage. Mosquitoes are holometabolous insects whose larvae develop in aquatic habitats, whereas the adults are terrestrial. Larval and adult stages are not independent from each other because the larval environment can influence adult life-history traits through carry-over effects. We recently provided experimental evidence for such carry-over effects in the mosquito Aedes aegypti, the main vector of dengue, yellow fever and Zika viruses. Using gnotobiotic mosquitoes, we demonstrated that larval exposure to different bacteria can cause variation in Ae. aegypti adult traits underlying vectorial capacity (Dickson et al. 2017). This proof of principle is an important first step toward a more comprehensive understanding of how the environment shapes the risk of vector-borne disease. However, the larval microbiota has not been thoroughly characterized across ecologically diverse breeding sites in the field. The aim of this project is to characterize the bacterial and fungal microbiota of Ae. aegypti breeding sites and larvae in Gabon using targeted metagenomics and metatranscriptomics.

Our research team recently identified an Aedes aegypti mosquito population that is partially resistant to dengue virus infection. We also have candidate genes that potentially innerly this phenotype. In this project, we would like to test wether specific SNPs are associated with virus infection in those mosquitoes. Sequencing data has already been generated with the Omics platform and handled by C3BI.

Lyme borreliosis (LB) is an important tick-borne disease which can cause a broad range of symptoms mainly affecting the skin, the nervous system and the joints. It is caused by bacteria of the Borrelia burgdorferi sensu lato (s.l.) complex. In Europe, at least five genospecies are known to be pathogenic, namely Borrelia afzelii, Borrelia garinii, B. burgdorferi sensu stricto, Borrelia spielmanii and Borrelia bavariensis. In order to assess the health burden, data on the incidence of all the different clinical manifestations are required. The National Reference Centre for Borrelia collected epdiemiological, clinical and biological data from general practioners and hospitals of patients bitten by Ixodes ticks from 2003 to 2011. This large amount of data needs statistical analyses both univariate and univariate in order to obtain a global and precise vision of all the elements allowing us to understand this disease, both in the complexity of its symptoms and its management but also in the context of its prevention.

Cepia mass produces two species of Anopheles mosquitoes for research teams studying malaria. The aim of this project is to assess 1) whether or not the compostion of the bacterial microbiota fluctuates over time and if so to what extent ; 2) if there are significant variations can these be correlated with the degree of infectability by plasmodium parasites and/or the fitness of the mosquitoes (measured by their survival rate).

We are currently characterising a set of genes that are involved in the yellow fever mosquito, Aedes aegypti, vector competence. We would like to investigate the polymorphisms of those genes using exome sequencing data.

The mechanisms underlying Anopheles mosquito susceptibility to malaria parasite infection in nature are not understood. We infected wild Anopheles pedigrees in West Africa to map loci for susceptibility to the human malaria parasite Plasmodium falciparum. Individuals from phenotyped pedigrees were entirely sequenced in order to identify and fine-map segregating loci.

The highest global malaria prevalence is in Africa, where the most important vectors are members of the Anopheles gambiae species complex. We generated a large curated panel of infected wild Anopheles gambiae mosquitoes in West Africa to analyze for association of genetic variants with susceptibility to the human malaria parasite Plasmodium falciparum.

Enhancers are cis-regulatory elements that control developmental and spatial gene expression in eukaryotes. Enhancers have been little studied in mosquitoes, including the Anopheles vectors of malaria.

Investigating the genetic basis of an organism’s phenotype typically focuses on genomic sequences annotated as genes. This traditional approach ignores repeated sequences such as transposable elements (TEs) that often make up a large fraction of the genome and contribute significantly to genetic diversity, including variation in genome size. TEs are mainly known to play an important role in genome architecture and evolution through their mutational potential but TE expression itself can also regulate gene expression and chromatin accessibility, activate cellular signaling pathways, and trigger aging or antiviral activities. In the mosquito Aedes aegypti, more than half of the genome consists of TEs but their contribution to phenotypic variation is virtually unknown. This aim of this project is to survey the variation in TE content and expression of Aedes aegypti mosquitoes using existing RNA-seq and DNA-seq datasets. It will lay the foundation for future studies on the functional relationships between TEs and phenotypes of interest.

This projects aims at performing transcriptomics on mosquitoes infected with arboviruses such as Dengue or Zika virus.

To better understand the vector specificity of Aedes aegypti mosquito in the transmission of CHIK virus, we try to identify genes involved in the primary responses of the viral infection when the virus is still in the midgut of mosquitoes, prior to the crossing of the gut epithelium. This investigation will be performed via mRNAseq from sequences of pools of 8 mosquitoes that fed on blood (controls) or on blood +CHIKV (infected mosquitoes).

Describing viruses of invertebrate vectors of disease, provides better understanding of evolution and host range for various virus groups. In addition to filling the gaps in the current knowledge of the virosphere, viromes can serve as necessary contextual data for ongoing disease control measures and outbreak preparedness. This project aims at delivering a comprehensive analysis of RNA viromes from RNA sequencing data.

Before the WHO considered it as a public health emergency of international concern in February 2016, Zika virus (ZIKV, Flavivirus, Flaviviridae) was a neglected mosquito-borne virus. First identified in Uganda in a sylvatic cycle, ZIKV has caused in few months millions cases, emerging in the five continents (Latin America, the Caribbean, Southeast Asia/Pacific Ocean, Africa/Indian Ocean, European countries (Portugal, Spain, France, Switzerland, the Netherlands)). We have initiated the most comprehensive study on vector competence with almost 50 mosquito populations belonging to five main species (Aedes aegypti, Aedes albopictus, Aedes japonicus, Culex pipiens, Culex quinquefasciatus) infected with 3 different ZIKV and examined at 3 days post-infection (7, 14, and 21). The objective of the project will be to run a meta analysis on vector competence and to assess to which extent each mosquito species contributes to ZIKV transmission according to the geographical location and the viral genotype. It will help to improve our understanding of the vector status and adapt surveillance, prevention, and control of Zika.

To better understand the vector specificity of Aedes aegypti mosquito in the transmission of the alphaviruses CHIKV and ONNV, we are using an in vitro system to specifically depict critical viral infection steps at the molecular level: transcription and replication of the viral genome. This in vitro system requires mosquito cell transfections followed by luciferase quantification. For better describe the viral replication in mosquito cells, we need to characterize our mosquito cell lines since it is well established that some insect specific viruses (ISVs) modulate arbovirus infection in vectors. In order to determine whether our mosquito cell lines are infected by ISVs , we have already sequenced respectively total and small RNAs of our cell lines: Aedes aegypti Aag2 cells and Anopheles cells ( 4A3a, 4A3a and SUA4). The analysis of these data will furnish global and comprehensive cell features regarding the presence of ISVs which may interfere with viral infections in mosquitoes.

We have performed a systemic characterisation of apoptosis distribution and clone dynamics in the Drosophila wing imaginal disc. Surprisingly, we outlined a systematic spatial bias in the rate of apoptosis with regions shoing high rates of apoptosis which correlate with high probability of clone disappearance and small clone size. We would like to formulate analytically the prediction of local clone size assuming a homogenous proliferation rate and knowing spatial differences in clone disappearance probability. This will help to evaluate how much the spatial differences in apoptic rates are sufficient to explain the differences in local growth.

The objective of this project is to study the virome present in specific bat colonies in China and their associated ectoparasites, in order to identify potential (re) emerging zoonotic viruses and to elucidate their transmission route, especially as putative arboviruses.

Several arboviruses have emerged and/or reemerged in the New World in the past decades. While yellow fever and dengue are historical diseases which continue to cause deadly epidemics, Zika and chikungunya have recently invaded the South American continent, causing great concern. In Colombia, Aedes aegypti is the vector of most of human arboviruses. We collected Ae. aegypti eggs in Medellin in Colombia in 2020 and infected adults with dengue (DENV), chikungunya (CHIKV), yellow fever (YFV) and Zika virus (ZIKV). We show that Ae. aegypti Nor Oriental was more prone to become infected, to disseminate and transmit CHIKV and ZIKV than DENV and YFV. In this project, we aim at determining the diversity of viral populations at the crossing of two anatomical barriers in mosquitoes: midgut and salivary glands.

We are interested in the behaviour of healthy cells in the context of tumour growth in the Drosophila brain We want to know the genes changing in healthy cells response to the tumour.