Biology subjects

Barwell, T.

Publications and source records attributed to Barwell, T..

6 recordsLinked to original sources

bioRxiv2026

EDTP Loss of Function Impairs Longevity and Reproduction

This study presents a comprehensive genetic characterization of DJ694, a viable GAL4 enhancer-trap allele of the age-regulated gene EDTP. EDTP transcript levels are reduced in DJ694, and homozygous flies exhibit reduced reproduction and shortened lifespan in both sexes. The fertility and longevity phenotypes are recessive and can be fully rescued by three independent UAS-EDTP insertions. Expression of UAS-EDTP into animals with wildtype phenotypes does not affect female fertility or lifespan. DJ694 has a jumpy behaviour but it is not detected by a locomotion assay. Like its human homolog, Muscle-specific Inositol Phosphatase (MIP, also known as MTMR14), EDTP is mainly expressed in adult muscles. The structure of the muscle, myofibril, and sarcomere appears normal in homozygous DJ694. DJ694 females have morphologically normal ovaries, implicating a functional rather than structural impairment. We demonstrate that EDTP is required during both development and adulthood to support normal fertility, with expression restricted to either stage alone being insufficient. Although it has been reported that EDTP can influence the accumulation of polyglutamine aggregates, we did not find evidence in its native tissue. Ectopic expression in the eye reduces the amount of aggregates but EDTP overexpression in muscles has no detectable effect on the accumulation or toxicity of two different kinds of polyglutamine aggregates.

genetics↗

bioRxiv2023

Juvenile and adult expression of polyglutamine expanded huntingtin produce distinct aggregate distributions in Drosophila muscle

While Huntingtons disease (HD) is widely recognized as a disease affecting the nervous system, much evidence has accumulated to suggest peripheral or non-neuronal tissues are affected as well. Here, we utilize the UAS/GAL4 system to express a pathogenic HD construct in the muscle of the fly, and characterize the effects. We observe detrimental phenotypes such as reduced lifespan, decreased locomotion, and accumulation of protein aggregates. Strikingly, depending on the GAL4 driver used to express the construct we saw different aggregate distributions and severity of phenotypes. These different aggregate distributions were found to be dependent on expression level and the timing of expression. Hsp70, a well-documented suppressor of polyglutamine aggregates, was found to strongly reduce the accumulation of aggregates in the eye, but in the muscle it did not prevent the reduction of the lifespan. Therefore, the molecular mechanisms underlying the detrimental effects of aggregates in the muscle are distinct from the nervous system.

genetics↗

bioRxiv2020

The RNA Structurome in the Asexual Blood Stages of Malaria Pathogen Plasmodium falciparum

RNA as an effector of biological functions often adopts secondary and tertiary structural folds. Plasmodium falciparum is a deadly human pathogen responsible for the devastating disease called malaria. In this study, we measured the differential accumulation of RNA secondary structures in coding and noncoding transcripts from the asexual developmental cycle in P. falciparum in human red blood cells. Our comprehensive analysis, combining high-throughput nuclease mapping of RNA structures by duplex RNA-seq, immunoaffinity purification and RNA analysis, collectively measured differentially base-paired RNA regions during the parasite development. Our mapping data not only aligned to a diverse pool of RNAs with known structures but also enabled us to identify new structural RNA regions in the malaria genome. On average, ~71% of the genes with secondary structures are found to be protein coding mRNAs. Mapping pattern of these base-paired RNAs corresponded to all parts of protein-coding mRNAs, including 5 UTR, CDS and 3 UTR. In addition to histone family genes which are known to form secondary structures in their mRNAs, transcripts from genes which are important for transcriptional and post-transcriptional control, such as unique plant-like transcription factor family, ApiAP2, DNA/RNA binding protein family, Alba, ribosomal proteins and eukaryotic initiation factors involved in translational control and the ones important for RBC invasion and cytoadherence also show strong accumulation of duplex RNA reads in various asexual stages. Intriguingly, our study determined a positive relationship between mRNA structural contents and translation efficiency in P. falciparum asexual blood stages, suggesting an essential role of RNA structural changes in malaria gene expression programs.

molecular biology↗

bioRxiv2020

Versatile Method to measure locomotion

Many studies require the ability to quantify locomotor behavior over time. The list of tracking softwares and their capabilities are constantly growing. At the 2019 CanFly Conference we presented preliminary results from an investigation of the effects of expressing polyglutamine repeats in fly muscles on longevity, locomotion and protein aggregation and received a lot of inquiries about our protocol to measure locomotion and how to use the FlyTracker MatLab software. This report describes a versatile locomotion measuring device and custom MatLab scripts for the extraction and analysis, and compilation of FlyTracker data in a format compatible with spreadsheet softwares. The measurement and analysis of multiple genotypes and both sexes across age shows that this method yields reproducible results that confirm that normal aging is associated with a progressive decline in locomotion as indicated by increased immobility and reduced velocity.

animal behavior and cognition↗

bioRxiv2019

Expression of heat shock protein 70 is insufficient to extend Drosophila melanogaster longevity

It has been known for over 20 years that Drosophila melanogaster flies with twelve additional copies of the hsp70 gene encoding the 70 kDa heat shock protein lives longer after a non-lethal heat treatment. Since the heat treatment also induces the expression of additional heat shock proteins, the biological effect can be due either to HSP70 acting alone or in combination. This study used the UAS/GAL4 system to determine whether hsp70 is sufficient to affect the longevity and the resistance to thermal, oxidative or desiccation stresses of the whole organism. We observed that HSP70 expression in the nervous system or muscles has no effect on longevity or stress resistance but ubiquitous expression reduces the life span of males. We also observed that the down-regulation of Hsp70 using RNAi did not affect longevity.

genetics↗

bioRxiv2017

Regulating the UAS/GAL4 system in adult Drosophila with Tet-off GAL80 transgenes

The UAS/GAL4 system is the most used method In Drosophila melanogaster for directing the expression of a gene of interest to a specific tissue. However, the ability to control the temporal activity of GAL4 with this system is very limited. This study constructed and characterized Tet-off GAL80 transgenes designed to allow temporal control of GAL4 activity in aging adults. By placing GAL80 under the control of a Tet-off promoter, GAL4 activity is regulated by the presence or absence of tetracycline in the diet. Almost complete inhibition of the expression of UAS transgenes during the pre-adult stages of the life cycle is obtained by using four copies and two types of Tet-off GAL80 transgenes. Upon treatment of newly emerged adults with tetracycline, induction of GAL4 activity is observed but the level of induction is influenced by the concentration of the inducer, the age, the sex and the anatomical location of the expression. The inhibition of GAL4 activity and the maintenance of induced expression is altered in old animals. This study reveals that the repressive ability of GAL80 is affected by the age and sex of the animal which is a major limitation to regulate gene expression with GAL80 in aged Drosophila.

genetics↗