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Biology subjects

Wood, M. L.

Publications and source records attributed to Wood, M. L..

4 recordsLinked to original sources

A ribosome exit tunnel component is required for robust expression of the Drosophila hox gene, abdominal A

Ribosomes, the molecular machines responsible for protein synthesis, are fundamental to all cellular life. Although the higher-level architecture of ribosomes is conserved, a small subunit acting as the mRNA decoding site and a large subunit that catalyses peptide bond formation, there are differences in the numbers of components of each of the subunits between the 3 domains of life. Despite their well-established role in translating genetic information into functional proteins, many complexities in ribosome biology and functionality are only just being revealed. Defects in ribosomal components contribute to a class of disorders termed ribosomopathies that come with a range of symptoms and severities. Here we show that a mutation in the Drosophila ribosomal protein RpL39 causes an anterior-posterior embryonic patterning defect through impaired accumulation of the hox protein Abdominal-A (abdA). Deletions uncovering subunits of the Nascent peptide-Associated Complex (NAC) and Ribosome-Associated Complex (RAC) act as genetic enhancers of the RpL39 mutation leading us to speculate that RpL39 forms a relay between the nascent peptide in the exit tunnel and the exterior surface of the ribosome, modulating the interaction with these ribosomally-associated complexes. This work enhances our knowledge of the roles played by individual ribosome components and feeds into our understanding of the mechanisms of ribosome quality control.

cell biology↗

Developmental stage-dependent decoupling of molecular and phenotypic responses to heat in wheat grain

Heatwaves during flowering and grain development threaten global wheat production, yet the extent to which developmental stage shapes molecular and phenotypic responses remains unclear. Here, we investigated whether heat stress (36/29{degrees}C for 48 h) imposed at closely spaced developmental stages surrounding anthesis generates stage-specific molecular responses that are associated with subsequent effects on grain properties. Heat exposure increased floret abortion most strongly when it was imposed at the trinucleate stage (TN; [~]48%) compared with the binucleate (BN) and early post-anthesis stages. Methylation levels were largely unaffected by prior heat treatments; however, heat induced stage- and locus-specific methylation changes, particularly at BN. Spatial RNA-seq revealed tissue-specific heat responses that were distinctively different in BN and TN. Integrated metabolomic analyses revealed stage-dependent metabolic reprogramming, including shifts towards stress-associated pathways. Despite heat stress at BN generating broader molecular reprogramming in developing grain, exposure at TN produced stronger effects on grain set and composition, revealing a decoupling between the magnitude of responses and phenotypic outcomes. Together, these findings demonstrate that subtle differences in developmental stage influence the complex molecular responses to heat and subsequent grain properties.

plant biology↗

Variation in Human Herpesvirus 6B telomeric integration, excision and transmission between tissues and individuals

Human herpesviruses 6A and 6B (HHV-6A/6B) are ubiquitous pathogens that persist lifelong in latent form and can cause severe conditions upon reactivation. They are spread by community-acquired infection of free virus (acqHHV6A/6B) and by germline transmission of inherited chromosomally- integrated HHV-6A/6B (iciHHV-6A/6B) in telomeres. We exploited a hypervariable region of the HHV- 6B genome to investigate the relationship between acquired and inherited virus and revealed predominantly maternal transmission of acqHHV-6B in families. Remarkably, we demonstrate that some copies of acqHHV-6B in saliva from healthy adults gained a telomere, indicative of integration and latency, and that the frequency of viral genome excision from telomeres in iciHHV-6B carriers is surprisingly high and varies between tissues. In addition, newly formed short telomeres generated by partial viral genome release are frequently lengthened, particularly in telomerase-expressing pluripotent cells. Consequently, iciHHV-6B carriers are mosaic for different iciHHV-6B structures, including circular extra-chromosomal forms that have the potential to reactivate. Finally, we show transmission of an HHV-6B strain from an iciHHV-6B mother to her non-iciHHV-6B son. Altogether we demonstrate that iciHHV-6B can readily transition between telomere-integrated and free virus forms.

genetics↗

Interspecific introgression reveals a role of male genital morphology during the evolution of reproductive isolation in Drosophila

Rapid divergence in genital structures among nascent species has been posited to be an early-evolving cause of reproductive isolation, although evidence supporting this idea as a widespread phenomenon remains mixed. Using a collection of interspecific introgression lines between two Drosophila species that diverged [~]240,000 years ago, we tested the hypothesis that even modest divergence in genital morphology can result in substantial fitness losses. We studied the reproductive consequences of variation in the male epandrial posterior lobes between Drosophila mauritiana and D. sechellia and found that divergence in posterior lobe morphology has significant fitness costs on several pre-fertilization and post-copulatory reproductive measures. Males with divergent posterior lobe morphology also significantly reduced the life span of their mates. Interestingly, one of the consequences of genital divergence was decreased oviposition and fertilization, which suggests that a sensory bias for posterior lobe morphology could exist in females, and thus posterior lobe morphology may be the target of cryptic female choice in these species. Our results provide evidence that divergence in genitalia can in fact give rise to substantial reproductive isolation early during species divergence, and they also reveal novel reproductive functions of the external male genitalia in Drosophila.

evolutionary biology↗