The periodical cicadas in the genus Magicicada are remarkable for their unusual life histories and dramatic synchronized emergences every 13 or 17 years. While aspects of their evolution, mating behaviors, and general biology have been well-characterized, there is surprising uncertainty surrounding the feeding habits of the short-lived adult stage. Despite a tentative scientific consensus to the contrary, the perception that adult Magicicada do not feed has persisted among the general public, and recent studies are lacking. We directly investigated the feeding behavior of Magicicada spp. through high-throughput sequencing (HTS)-based dietary analysis of nymphs, freshly molted (teneral) adults, and fully sclerotized adults collected from orchard and wooded habitats during the 2021 emergence of Brood X. Identifiable plant DNA (trnF, ITS amplicons) was successfully recovered from nymphs and adults. No plant DNA was recovered from teneral adults, suggesting that all DNA recovered from sclerotized adults was ingested during the post-teneral adult stage. Both nymphs and adults were found to have ingested a range of woody and herbaceous plants across 17 genera and 14 families. Significantly more plant genera per individual were recovered from adults than from nymphs, likely reflecting the greater mobility of the adult stage. We hypothesize that the demonstrated ingestion of plant sap by Magicicada adults is driven by a need to replace lost water and support specialized bacteriome-dwelling endosymbionts that cicadas depend upon for growth and development, which constitutes true feeding behavior.

RNA alternative polyadenylation contributes to the complexity of information transfer from genome to phenome, thus amplifying gene function. Here, we report the first X. tropicalis resource with 127,914 alternative polyadenylation (APA) sites derived from embryos and adults. Overall, APA networks play central roles in coordinating the maternal–zygotic transition (MZT) in embryos, sexual dimorphism in adults and longitudinal growth from embryos to adults. APA sites coordinate reprogramming in embryos before the MZT, but developmental events after the MZT due to zygotic genome activation. The APA transcriptomes of young adults are more variable than growing adults and male frog APA transcriptomes are more divergent than females. The APA profiles of young females were similar to embryos before the MZT. Enriched pathways in developing embryos were distinct across the MZT and noticeably segregated from adults. Briefly, our results suggest that the minimal functional units in genomes are alternative transcripts as opposed to genes.

Construction of next-generation sequencing (NGS) libraries involves RNA manipulation, which often creates noisy, biased, and artifactual data that contribute to errors in transcriptome analysis. In this study, a total of 19 whole transcriptome termini site sequencing (WTTS-seq) and seven RNA sequencing (RNA-seq) libraries were prepared from Xenopus tropicalis adult and embryo samples to determine the most effective library preparation method to maximize transcriptomics investigation. We strongly suggest that appropriate primers/adaptors are designed to inhibit amplification detours and that PCR overamplification is minimized to maximize transcriptome coverage. Furthermore, genome annotation must be improved so that missing data can be recovered. In addition, a complete understanding of sequencing platforms is critical to limit the formation of false-positive results. Technically, the WTTS-seq method enriches both poly(A)+ RNA and complementary DNA, adds 5′- and 3′-adaptors in one step, pursues strand sequencing and mapping, and profiles both gene expression and alternative polyadenylation (APA). Although RNA-seq is cost prohibitive, tends to produce false-positive results, and fails to detect APA diversity and dynamics, its combination with WTTS-seq is necessary to validate transcriptome-wide APA.

Daily HBO2 treatment over four days produces an antinociceptive effect of unusually long duration in mice (Chung et al., J. Pain 11:847, 2010). The mechanism by which HBO2 produces this long-acting antinociception remains unknown although we have reported that intracerebroventricular perfusion with the nitric oxide synthase-inhibitor L-NG-nitro arginine methyl ester interfered with development of the late-phase antinociceptive response. We performed an oligonucleotide microarray analysis to determine whether HBO2 induced gene changes that might be associated with the long-lasting antinociceptive effect. Male NIH Swiss mice were exposed to NBA (air at 1.0 ATA), NBO2 (100% O2 at 1.0 ATA), HBA (air at 3.5 ATA) or HBO2 (100% O2 at 3.5 ATA) for 60 min daily on four consecutive days. Mice were killed at 9, 24 and 72 h after the final exposure and total RNA was collected from whole brain homogenate. Results showed that, compared to room air-exposed controls, a total of 12 genes were altered by 2-fold or more. Genes from HBO2-treated mice that significantly increased between 9 and 24 hr included Arc, Egr2, Fos and Nr4a1. Genes that showed a significant decrease between 9 and 24 hr included Hif3a, Sgk1 and Fkbp5. (Supported in part by NIH Grant GM-77153 and the Allen I. White Distinguished Professorship.)

Histone N-terminal domains are frequent targets of posttranslational modifications. Multiple acetylated lysine residues have been identified in the N-terminal domain of H2B (K6, K11, K16, K17, K21, and K22), but little is known about how these modifications regulate transcription. We systematically mutated the N-terminal domain of histone H2B, both at known sites of lysine acetylation and elsewhere, and characterized the resulting changes in genome-wide expression in each mutant strain. Our results indicate that known sites of lysine acetylation in this domain are required for gene-specific transcriptional activation. However, the entire H2B N-terminal domain is principally required for the transcriptional repression of a large subset of the yeast genome. We find that the histone H2B repression (HBR) domain, comprised of residues 30 to 37, is necessary and sufficient for this repression. Many of the genes repressed by the HBR domain are located adjacent to telomeres or function in vitamin and carbohydrate metabolism. Deletion of the HBR domain also confers an increased sensitivity to DNA damage by UV irradiation. We mapped the critical residues in the HBR domain required for its repression function. Finally, comparisons of these data with previous studies reveal that a surprising number of genes are coregulated by the N-terminal domains of histone H2B, H3, and H4.

The transcription of genes located in subtelomeric regions of yeast chromosomes is repressed relative to the rest of the genome. This repression requires wild-type nucleosome levels but not the telomere silencing factors Sir2, Sir3, Sir4, and Rap1. Subtelomeric heterochromatin is characterized by the absence of acetylation or methylation of histone H3 lysine residues, but it is not known whether histone H3 hypoacetylation or hypomethylation is a prerequisite for the establishment of subtelomeric heterochromatin. We have systematically mutated the N-terminal tails of histone H3 and H4 in Saccharomyces cerevisiae and characterized the effects each mutant has on genome-wide expression. Our results show that subtelomeric transcriptional repression is dependent on the histone H3 N-terminal domain, but not the histone H4 N-terminal domain. Mutating lysine-4, lysine-9, lysine-14, lysine-18, lysine-23, and lysine-27 to glycine in histone H3 is also sufficient to significantly reduce subtelomeric gene repression. Individual histone H3 lysine mutations, however, have little effect on subtelomeric gene repression or genome-wide expression, indicating that these six lysine residues have redundant functions. We propose that acetylation and methylation of histone H3 N-terminal lysine residues act as redundant mechanisms to demarcate regions of euchromatin from heterochromatin.