N6-adenosine (m6A) mRNA methylation is required for Tribolium castaneum development and reproduction

Identification of Histone and N-Terminal Acetyltransferases Required for Reproduction and Embryonic Development of Yellow Fever Mosquito, Aedes aegypti

Histone acetylation levels maintained by histone acetyltransferases (HATs) and histone deacetylases play important roles in maintaining local chromatin accessibility and expression of genes that regulate many biological processes, including development and reproduction. N-terminal acetylation of proteins catalyzed by N-terminal acetyltransferases (NATs) also regulates gene expression. We identified 25 HATs/NATs genes in the yellow fever mosquito, Aedes aegypti, and investigated their function in female reproduction using RNA interference (RNAi). Among the HATs/NATs studied, the knockdown of AANAT1 (Arylamine N-acetyltransferase), NAA40 (N-alpha-acetyltransferase 40), NAA80 (N-alpha-acetyltransferase 80), KAT7 (Histone lysine acetyltransferase 7), ACNAT (Acyl-CoA N-acyltransferase), and MCM3AP (Minichromosome maintenance complex component 3 associated protein) significantly reduced egg laying and caused severe problems in oocyte development compared to that in control insects injected with dsGFP. Gene expression analysis using RT-qPCR revealed that vitellogenin and its receptor genes are downregulated in mosquitoes injected with dsAANAT1, dsNAA40, dsNAA80, dsKAT7, dsACNAT, and dsMCM3AP compared to that in control animals. Also, the knockdown of HATs/NATs genes ATAT1 (Alpha-tubulin N-acetyltransferase 1), AANAT1, TAFIID (Transcription initiation factor TFIID subunit 1), HATB (Histone acetyltransferase type B) and NAT9 (N-acetyltransferase 9) decreased more than 50% egg hatch by blocking embryonic development. These results suggest that the acetylation of proteins, especially histones mediated by NATs and HATs, plays an important role in regulating female reproduction and embryonic development of Ae. aegypti.

Comparative Proteomic Analysis Reveals Altered Ciliary Proteins in Sickle Cell Disease

Sickle cell disease (SCD) is an inherited hemoglobinopathy characterized by sickle-shaped red blood cells (RBCs). Primary cilia are mechanosensory organelles and are projected in the lumen of blood vessels to detect blood flow. We previously reported that interaction between microvasculature endothelial cells and sickled RBCs resulted in altered blood flow that can elevate reactive oxygen species, leading to increased deciliation in SCD patients. However, the impact of deciliation mediated by sickled RBCs in the context of the ciliary protein profiles remains unclear. Here, we investigated cell-cilia stability under different physiological shear-stress magnitudes and examined cilia protein profiles in SCD, utilizing mouse models and human participants. Our results demonstrate that subjecting endothelial cilia to sickled RBCs at 5.0 dyn/cm2 led to significant deciliation events. The proteomic and bioinformatic analyses showed different ciliary protein profiles, distinct signaling pathways, and unique post-translational modification processes in the SCD mouse model. Consistent with the SCD mouse model results, our translational studies validated the enrichment of specific proteins, including Transferrin Receptor-1 (TfR1), Glyceraldehyde-3-Phosphate-Dehydrogenase (GAPDH), and ADP Ribosylation Factor Like GTPase-13B (ARL13B) in SCD patients. These findings underscore the clinical relevance of cilia in SCD and suggest that ciliary proteins are potential biomarkers for assessing vascular damage.

Epigenomic Changes in Ostrinia Moths Under Elevated Pupal and Adult Temperature

Epigenetic changes in the methylation of DNA may occur in response to environmental stressors, including warming climates. DNA methylation may also play an important role in regulating gene expression during both male and female reproduction in many insect species. However, it is currently unknown how DNA methylation shifts when individuals are reproducing under warmer temperatures. We exposed European corn borer moths (Ostrinia nubilalis) to heat during the pupal and adult life stages then investigated changes in DNA methylation across the genome using enzymatic methyl-seq (EM-seq). We compared methylation patterns in reproductive males and females exposed to heat (28°C) to those that experienced an ambient temperature (23°C). We found that heat exposure led to a small but significant increase in the percentage of methylated CpG sites throughout the genome in both sexes. However, DNA methylation rates were higher in females and differential methylation following heat exposure localised to unique regions in each sex. In males, methylation shifted within genes belonging to pathways including Hippo signalling, ubiquitin-mediated proteolysis, DNA damage repair and spermatogenesis. In females, differential methylation occurred in genes related to histone modification and oogenesis. Our results suggest that DNA methylation patterns respond to moderate heat exposure in Lepidoptera and provide insight into epigenetic responses to heatwaves, suggesting novel pathways that may be involved in responding to heat stress during metamorphosis and reproduction.

RNA modifications in insects

More than 100 RNA chemical modifications to cellular RNA have been identified. N 6-methyladenosine (m6A) is the most prevalent modification of mRNA. RNA modifications have recently attracted significant attention due to their critical role in regulating mRNA processing and metabolism. tRNA and rRNA rank among the most heavily modified RNAs, and their modifications are essential for maintaining their structure and function. With our advanced understanding of RNA modifications, increasing evidence suggests RNA modifications are important in regulating various aspects of insect life. In this review, we will summarize recent studies investigating the impact of RNA modifications in insects, particularly highlighting the role of m6A in insect development, reproduction, and adaptation to the environment.

Untangling the gordian knot: The intertwining interactions between developmental hormone signaling and epigenetic mechanisms in insects

Hormones control developmental and physiological processes, often by regulating the expression of multiple genes simultaneously or sequentially. Crosstalk between hormones and epigenetics is pivotal to dynamically coordinate this process. Hormonal signals can guide the addition and removal of epigenetic marks, steering gene expression. Conversely, DNA methylation, histone modifications and non-coding RNAs can modulate regional chromatin structure and accessibility and regulate the expression of numerous (hormone-related) genes. Here, we provide a review of the interplay between the classical insect hormones, ecdysteroids and juvenile hormones, and epigenetics. We summarize the mode-of-action and roles of these hormones in post-embryonic development, and provide a general overview of epigenetic mechanisms. We then highlight recent advances on the interactions between these hormonal pathways and epigenetics, and their involvement in development. Furthermore, we give an overview of several 'omics techniques employed in the field. Finally, we discuss which questions remain unanswered and possible avenues for future research.