Biology subjects

Senti, K. A.

Publications and source records attributed to Senti, K. A..

4 recordsLinked to original sources

bioRxiv2024

In-cell structure and snapshots of copia retrotransposons in intact tissue by cryo-electron tomography

Long terminal repeat (LTR) retrotransposons belong to the transposable elements (TE), autonomously replicating genetic elements that integrate into the hosts genome. LTR retrotransposons represent a major component of genomes across the tree of life; some derived sequences have even been domesticated by the host to perform cellular functions in essential processes such as development. Among animals, Drosophila melanogaster serves as an important model organism for TE research, harboring several LTR retrotransposons, including the Ty1-copia family, which is evolutionarily related to retroviruses and forms virus-like particles (VLPs). The architectural organization of copia VLPs in situ has remained unknown. In this study, we use cryo-FIB milling and lift-out approaches to visualize copia VLPs in isolated ovarian cells and intact egg chambers and resolve the in situ copia capsid structure to 7.7 [A] resolution by cryo-ET. While cytosolic copia VLPs vary in size, nuclear VLPs are homogenous and form densely packed clusters, supporting a model in which nuclear import acts as a size selector. By analyzing flies deficient in the TE-suppressing PIWI-piRNA pathway, we observe a change in copia localization from cytosolic to nuclear during spermatogenesis in testes. Our findings provide insights into the cellular structural biology of an active LTR retrotransposon and shed light on the replication cycle of copia in the context of host gametogenesis.

biophysics↗

bioRxiv2022

Scavenger receptor endocytosis controls apical membrane morphogenesis in the Drosophila airways

The acquisition of distinct branch sizes and shapes is a central aspect in tubular organ morphogenesis and function. In the Drosophila airway tree, the interplay of apical ECM components with the underlying membrane and cytoskeleton controls tube elongation, but the link between ECM composition with apical membrane morphogenesis and tube size regulation is elusive. Here, we characterized Emp (epithelial membrane protein), a Drosophila CD36-homologue belonging to the scavenger receptor class B protein-family. emp mutant embryos fail to internalize the luminal chitin deacetylases Serp and Verm at the final stages of airway maturation and die at hatching with liquid filled airways. Emp localizes in apical epithelial membranes and shows cargo selectivity for LDLr-domain containing proteins. emp mutants also display over elongated tracheal tubes with increased levels of the apical proteins Crb, DE-cad and phosphorylated Src (p-Src). We show that Emp associates and organizes the {beta}H-Spectrin cytoskeleton and is itself confined by apical F-actin bundles. Overexpression or loss of its cargo protein Serp lead to abnormal apical accumulations of Emp and perturbations in p-Src levels. We propose that during morphogenesis, Emp senses and responds to luminal cargo levels by initiating apical membrane endocytosis along the longitudinal tube axis and thereby restricts airway elongation.

developmental biology↗

bioRxiv2021

A genetic toolkit for studying transposon control in the Drosophila melanogaster ovary

Argonaute proteins of the PIWI class complexed with PIWI-interacting RNAs (piRNAs) protect the animal germline genome by silencing transposable elements. One of the leading experimental systems for studying piRNA biology is the Drosophila melanogaster ovary. In addition to classical mutagenesis, transgenic RNA interference (RNAi), which enables tissue-specific silencing of gene expression, plays a central role in piRNA research. Here, we establish a versatile toolkit focused on piRNA biology that combines germline transgenic RNAi, GFP marker lines for key proteins of the piRNA pathway, and reporter transgenes to establish genetic hierarchies. We compare constitutive, pan-germline RNAi with an equally potent transgenic RNAi system that is activated only after germ cell cyst formation. Stage-specific RNAi allows us to investigate the role of genes essential for germline cell survival, for example nuclear RNA export or the SUMOylation pathway, in piRNA-dependent and independent transposon silencing. Our work forms the basis for an expandable genetic toolkit provided by the Vienna Drosophila Resource Center.

genetics↗

bioRxiv2019

Neuronal function and dopamine signaling evolve at high temperature in Drosophila

Introduction Introduction Main Methods Author contributions Competing interest Materials and Correspondence References Adaptation to local environments is a general principle in nature. In the light of the ongoing climatic change, the mechanisms for temperature adaptation are of particular interest1-2. Many essential biological processes are temperature sensitive, and neuronal activity3-7 is a particularly prominent one as it affects essential, fitness-related traits such as behavior and locomotion8. Here, we investigate if temperature stress triggers adaptation of neuronal signaling. We used replicated laboratory evolution experiments with Drosophila simula ...

evolutionary biology↗