Biology subjects

Logullo, C.

Publications and source records attributed to Logullo, C..

4 recordsLinked to original sources

bioRxiv2025

Loss of Vitellogenin Receptor Function Results in Yolk Depletion, Virome Expansion and Reduced Bacterial Load Within the Oocytes of Rhodnius prolixus

The vitellogenin receptor (VgR) mediates yolk protein uptake during oogenesis and is essential for embryogenesis in oviparous species. Here we characterize the single Rhodnius prolixus VgR isoform and uncover an unexpected role in microbial regulation within the reproductive system. The receptor displays a conserved LDLR-like structure and is highly expressed in early oocytes. RNAi-mediated VgR silencing caused defective yolk granule biogenesis, leading to the accumulation of the main yolk protein precursors, Vg and RHBP, in the hemolymph, yet oviposition and fertilization proceeded normally. The resulting eggs were yolk-depleted and non-viable. Remarkably, VgR knockdown reduced bacterial 16S rRNA levels in oocytes while promoting the expansion of several members of the core virome, a phenotype not reproduced by Vg silencing. Neither purified Vg nor changes in immune (defensin) or RNA interference pathways explained the microbial shifts. These findings indicate that VgR governs not only yolk endocytosis but also the trafficking of microbial components into developing oocytes. We propose that VgR contributes to the linking of yolk endocytic dynamics and microbial homeostasis, influencing the balance of microbial components within developing oocytes. This connection broadens the functional scope of the VgR and provides new insight into how vertical transmission processes are shaped in this major Chagas disease vector. Author summaryEgg-laying animals must load their eggs with enough nutrients to support early development. In insects, this process depends on a receptor that brings yolk proteins into the growing egg. Here, we studied this receptor in Rhodnius prolixus, a major vector of Chagas disease, and uncovered an unexpected link between yolk uptake and the microorganisms that enter the egg. When we blocked the receptor, females continued to produce and lay eggs, but these eggs failed to accumulate yolk and could not support embryonic development. Strikingly, the absence of the receptor also shifted the microbial community inside the oocyte: bacterial levels dropped, while several viruses expanded. These changes did not result from differences in yolk proteins, immune activation, or direct antimicrobial effects, indicating that the receptor itself influences microbial entry or persistence in the egg. Our findings reveal that this yolk receptor plays a dual role, providing nutrients and shaping the microbial community that is passed from mother to offspring. This work highlights an unrecognized layer of interaction between reproduction and microbial transmission in an important disease vector, offering new perspectives for understanding and potentially disrupting vertical transmission pathways.

cell 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↗

bioRxiv2020

The smORF-containing gene mille-pattes is required for moulting and Trypanosoma cruzi metacyclogenesis in the Chagas disease vector Rhodnius prolixus

Chagas disease is estimated to affect 8 million people worldwide and is responsible for circa 10,000 deaths in Latin America every year. Vector control has been developed as the main strategy to control disease spreading. The identification of new targets is essential, and genes containing small open reading frames (smORFs - < 100 amino acids) are present as hundreds of putative new candidate targets in insect genomes. Here, we show that the prototypic smORF containing gene mille-pattes/polished-rice/tarsalless (mlpt/pri/tal) is essential for post-embryonic development of the kissing bug Rhodnius prolixus and for the metacyclogenesis of the Trypanosoma cruzi parasite during nymphal stages. Injection of double-stranded RNA against mlpt (Rp-dsmlpt) during nymphal stages leads to a plethora of phenotypes which impairs post-embryonic development. First, nymphs of fourth or fifth stage injected with Rp-dsmlpt do not moult. Second, vector digestive physiology is largely modified, and haemozoin is significantly increased in the posterior midgut of Rp-dsmlpt nymphs. Third, Rp-mlpt knockdown inhibits the metacyclogenesis of Trypanosoma cruzi, the etiologic agent of Chagas disease. Thus, our study provides the first evidence of a smORF-containing gene regulating vector physiology, parasitic cycle and disease transmission.

molecular biology↗

bioRxiv2019

Multiple roles of the polycistronic gene tarsaless/mille-pattes/polished-rice during embryogenesis of the kissing bug Rhodnius prolixus

Genes encoding small open-reading frames (smORFs) have been characterized as essential players of developmental processes. The smORF tarsaless/mille-pattes/polished-rice has been thoroughly investigated in holometabolous insects, such as the fruit fly Drosophila melanogaster and the red flour beetle Tribolium castaneum, while its function in hemimetabolous insects remains unknown. Thus, we analyzed the function of the tal/pri/mlpt ortholog in a hemimetabolous insect, the kissing bug Rhodnius prolixus (Rp). First, sequence analysis shows that Rp-tal/pri/mlpt polycistronic mRNA encodes two small peptides (11 to 14 amino acids) containing a LDPTG motif. Interestingly, a new hemipteran-specific conserved peptide of approximately 80 amino acids was also identified by in silico analysis. In silico docking analysis supports the high-affinity binding of the small LDPTG peptides to the transcription factor Shavenbaby. Rp-tal/pri/mlpt in situ hybridization and knockdown via RNA interference showed a conserved role of Rp-tal/pri/mlpt during embryogenesis, with a major role in the regulation of thoracic versus abdominal segmentation, leg development and head formation. Altogether, our study shows that tal/pri/mlpt segmentation role is conserved in the common ancestor of Paraneoptera and suggests that polycistronic genes might generate order specific smORFs.

developmental biology↗