Condition-responsive growth is a common feature of multicellular development, during which organisms integrate genetic and environmental signals to adjust their phenotype. However, the molecular properties shaping condition-responsive diversification remain poorly understood. The beetle genus Onthophagus offers promising opportunities to investigate this question, given its diversity of sex- and nutrition-responsive phenotypes, including horns — novel, secondary sexual weapons used in reproductive competition. We compared the gene regulatory properties of horns in two closely related species exhibiting highly specialized sex- and nutrition-biased phenotypes. We found a dynamic cis -regulatory landscape in developing horn tissue, shaped by mutational accumulation across species, condition-specific changes in chromatin accessibility within species, and the acquisition of lineage-specific regulatory elements. Many of these putative regulatory regions include binding site motifs of critical developmental regulatory genes, including members of the bone morphogenetic protein signaling pathway. We provide functional evidence that two proteins in this pathway have been co-opted for horn development, influencing the shape and size of this trait across species, sexes, and nutritional states. These findings provide evidence that evolutionarily labile cis -regulatory interactions may evolve alongside diversification of condition-specific traits, potentially modifying the activity of conserved developmental pathways over short evolutionary timescales.
Neuroligin-3 ( NLGN3 ) was first identified as a X-linked risk gene associated with autism spectrum disorder (ASD). Most reported variants are identified in males who inherited their variants from an unaffected mother, but de novo variants have also been identified in both affected heterozygous females and hemizygous males. The p.R451C variant was the initial variant associating NLGN3 with ASD and has been heavily investigated, yet little is known about the functional consequences of other NLGN3 variants. To determine the functional consequences of other NLGN3 variants in vivo , we generated transgenic Drosophila models corresponding to a de novo variant (p.R175W) identified in a heterozygous female proband with ASD, a maternally inherited variant (p.R451C) identified in a hemizygous male with ASD, and another maternally inherited variant identified in a male (p.R597W) associated with sleep disorder and ASD. In Drosophila , loss of the fly homolog, Nlg3, altered sleep patterns, synaptic architecture, and vesicle dynamics, which were rescued by the expression of the human NLGN3 Ref allele. When comparing the variants, the p.R175W variant and the maternally inherited p.R451C variant altered synapse morphology with minimal effects on vesicle dynamics, and the p.R597W variant altered sleep and vesicle dynamics with minimal impact on synapse morphology. Using overexpression models, human NLGN3 Ref altered sleep patterns and synaptic morphology. Moreover, the p.R175W variant exacerbated sleep phenotypes, and the p.R175W and p.R451C variants exacerbated synapse morphology phenotypes. Together, our findings suggest that the de novo NLGN3 p.R175W variant identified in a heterozygous female exhibits gain-of-function properties, while maternally inherited variants have context-dependent functional impact. Moreover, some NLGN3 variants disrupt synaptic development, while other variants alter synaptic function, suggesting that NLGN3 variants have differential effects. These functional differences may provide insight into the heterogeneity of individuals with ASD.
Screening for gastric cancer (GC) is critical for improving patient survival, yet current clinical methods suffer from invasiveness and limited sensitivity. The aim of this study is to develop a machine learning model for the non-invasive diagnosis of GC using the whole-genome methylation profile of circulating free DNA (cfDNA) in plasma. Plasma cfDNA from 61 patients with GC and 29 healthy controls. First, whole‑genome bisulfite sequencing (WGBS) was performed on 29 paired GC and adjacent normal tissues to identify differentially methylated regions (DMRs). These tissue DMRs were then mapped to plasma cfDNA methylation data, yielding 32 stable DMRs that changed consistently in both tissues and plasma. Using LASSO and Random Forest (RF) algorithms, eight core diagnostic markers were selected. Four machine learning algorithms (Support Vector Machine, RF, K-Nearest Neighbor, Naïve Bayes) were used to build diagnostic models. WGBS revealed global hypomethylation and CpG island hypermethylation in GC, consistent with plasma cfDNA methylation patterns. The RF model built on the eight cfDNA methylation markers (annotated to genes including ATP8A2) performed best, achieving AUC values of 0.978 and 0.938 in the training and independent test sets, respectively, with an accuracy of 88.46%, sensitivity of 94.44%, and specificity of 75.00%. After adjusting for age, the model achieved an AUC of 0.924 on the test set, still demonstrating high discriminatory performance. Functional analysis implicated these markers in pathways such as phagocytosis and axon guidance, and showed significant correlation with immune cell infiltration. Notably, these core DMRs are not covered by the probes on the methylation arrays (450K and EPIC v2), highlighting the advantage of WGBS for novel biomarker discovery. In conclusion, tissue-plasma concordance analysis identified a panel of plasma cfDNA methylation biomarkers with strong diagnostic potential. The resulting RF model provides a promising non-invasive strategy for GC screening.
Archaea have several cell surface structures belonging to the type 4 filament (T4F) superfamily. All share a minimal core assembly system consisting of an ATPase, a platform protein, a filament-forming protein, and a class III signal peptidase. Here, we generated novel MacSyFinder2 models to identify and classify archaeal T4F systems. Our analysis revealed a vast diversity of archaeal T4F, with many organisms harboring one or more assembly machineries. Structure-based phylogenetic analysis showed that the variable N-terminal domain of T4F-related ATPases mirrors the subsystem clustering, indicating that the core machinery has diversified within the archaeal secretion ATPase family through structural innovation. Genome-wide screening for signal peptidase III cleavage site (SPIII) containing proteins revealed the widespread presence of substrate-binding proteins carrying a class III signal peptide. We propose that these binding proteins, with canonical SPIII cleavage sites, functionalize T4F machineries for efficient substrate scavenging, expanding the functional repertoire of archaeal T4F systems beyond their currently characterized roles.
Tunicates are the sister group to vertebrates within the chordate phylum, yet unlike other chordate groups, they evolved a biphasic lifecycle alternating between motile larvae and sessile adults. The papillae of most tunicate larvae are the key sensory-adhesive organ regulating their settlement and metamorphosis. The papillae are nearly always arranged as a group of three morphologically identical organs that arise from an anterior neural plate border region nested between ventral epidermis and more dorsal/posterior neural tube progenitors. Due to their embryonic origin and molecular signatures, this anterior border has been evolutionarily linked to vertebrate placode regions. It was previously shown that the specification, patterning, and morphogenesis of the embryonic papilla region all depend on BMP signaling, though downstream mechanisms remain poorly understood. Here we show that the NKX2-3/5/6 ortholog NK4 is a key transcription factor that acts downstream of BMP signaling to pattern the papillae in the Ciona embryo. We present evidence that NK4 is activated by BMP signaling and encodes a transcriptional repressor that is required to restrict the expression of the papilla regulatory gene Foxg to three cell clusters that give rise to the three papillae. Loss of NK4 function results in the formation of a single large papilla. In contrast, overexpression of NK4 represses Foxg, eliminating the papillae. We also show that the expression of NK4 is restricted dorsally by the BMP antagonist Chordin, while the ventrally-expressed transcription factor Msx can alleviate the repressive effect of NK4, potentially allowing for the characteristic tripartite patterning of the papillae.
