Functional Metabolomics Describes the Yeast Biosynthetic Regulome.

Genome-metabolism interactions enable cell growth. To probe the extent of these interactions and delineate their functional contributions, we quantified the Saccharomyces amino acid metabolome and its response to systematic gene deletion. Over one-third of coding genes, in particular those important for chromatin dynamics, translation, and transport, contribute to biosynthetic metabolism. Specific amino acid signatures characterize genes of similar function. This enabled us to exploit functional metabolomics to connect metabolic regulators to their effectors, as exemplified by TORC1, whose inhibition in exponentially growing cells is shown to match an interruption in endomembrane transport. Providing orthogonal information compared to physical and genetic interaction networks, metabolomic signatures cluster more than half of the so far uncharacterized yeast genes and provide functional annotation for them. A major part of coding genes is therefore participating in gene-metabolism interactions that expose the metabolism regulatory network and enable access to an underexplored space in gene function.

An RNA-informed dosage sensitivity map reflects the intrinsic functional nature of genes.

Understanding dosage sensitivity or why Mendelian diseases have dominant vs. recessive modes of inheritance is crucial for uncovering the etiology of human disease. Previous knowledge of dosage sensitivity is mainly based on observations of rare loss-of-function mutations or copy number changes, which are underpowered due to ultra rareness of such variants. Thus, the functional underpinnings of dosage constraint remain elusive. In this study, we aim to systematically quantify dosage perturbations from cis-regulatory variants in the general population to yield a tissue-specific dosage constraint map of genes and further explore their underlying functional logic. We reveal an inherent divergence of dosage constraints in genes by functional categories with signaling genes (transcription factors, protein kinases, ion channels, and cellular machinery) being dosage sensitive, while effector genes (transporters, metabolic enzymes, cytokines, and receptors) are generally dosage resilient. Instead of being a metric of functional dispensability, we show that dosage constraint reflects underlying homeostatic constraints arising from negative feedback. Finally, we employ machine learning to integrate DNA and RNA metrics to generate a comprehensive, tissue-specific map of dosage sensitivity (MoDs) for autosomal genes.

The tree peony nuclear factor Y transcription factor PrNF-YC2 promotes seed oil accumulation.

Seed oil not only provides energy for seed postgermination development but also provides essential nutrients and raw materials for human products. However, the transcriptional regulatory mechanism controlling seed oil accumulation remains largely unknown. Tree peony (Paeonia rockii) is an emerging woody oilseed crop in China that is known for its high-quality seed oil. Here, we revealed that a tree peony nuclear factor Y transcription factor, PrNF-YC2, is expressed predominantly in developing seeds and functions as an essential positive regulator of seed oil accumulation. PrNF-YC2 promoted oil accumulation in both transient ectopic overexpression Nicotiana benthamiana leaves and stable transgenic Arabidopsis thaliana seeds, globally upregulating the expression of genes involved in oil accumulation. In contrast, PrNF-YC2-silenced tree peony leaves using a virus-induced gene silencing system showed reduced oil content and expression of oil synthesis-related genes, including four master positive regulators contributing to oil accumulation, namely, LEAFY COTYLEDON1 (LEC1), ABSCISIC ACID INSENSITIVE3 (ABI3), FUSCA3 (FUS3), and WRINKLED1 (WRI1). We demonstrated that PrNF-YC2 directly activates PrLEC1 and PrABI3 alone and indirectly activates PrFUS3 and PrWRI1 by interacting with PrLEC1. Moreover, interaction with PrLEC1 also enhances the activation capacity of PrNF-YC2. The activation of these four master positive regulators by PrNF-YC2 triggered the upregulation of numerous oil synthesis-related genes, thus promoting oil accumulation. These findings provide new insights into the regulatory mechanism of seed oil accumulation and manipulation of PrNF-YC2 may be beneficial for enhancing oil yield in tree peony and other oilseed crops.

Genes divided according to the relative position of the longest intron show increased representation in different KEGG pathways.

Despite the fact that introns mean an energy and time burden for eukaryotic cells, they play an irreplaceable role in the diversification and regulation of protein production. As a common feature of eukaryotic genomes, it has been reported that in protein-coding genes, the longest intron is usually one of the first introns. The goal of our work was to find a possible difference in the biological function of genes that fulfill this common feature compared to genes that do not. Data on the lengths of all introns in genes were extracted from the genomes of six vertebrates (human, mouse, koala, chicken, zebrafish and fugu) and two other model organisms (nematode worm and arabidopsis). We showed that more than 40% of protein-coding genes have the relative position of the longest intron located in the second or third tertile of all introns. Genes divided according to the relative position of the longest intron were found to be significantly increased in different KEGG pathways. Genes with the longest intron in the first tertile predominate in a range of pathways for amino acid and lipid metabolism, various signaling, cell junctions or ABC transporters. Genes with the longest intron in the second or third tertile show increased representation in pathways associated with the formation and function of the spliceosome and ribosomes. In the two groups of genes defined in this way, we further demonstrated the difference in the length of the longest introns and the distribution of their absolute positions. We also pointed out other characteristics, namely the positive correlation between the length of the longest intron and the sum of the lengths of all other introns in the gene and the preservation of the exact same absolute and relative position of the longest intron between orthologous genes.

DhuFAP: a platform for gene functional analysis in Dendrobium huoshanense.

BACKGROUND: Dendrobium huoshanense, a traditional medicinal and food plant, has a rich history of use. Recently, its genome was decoded, offering valuable insights into gene function. However, there is no comprehensive gene functional analysis platform for D. huoshanense. RESULT: To address this, we created a platform for gene function analysis and comparison in D. huoshanense (DhuFAP). Using 69 RNA-seq samples, we constructed a gene co-expression network and annotated D. huoshanense genes by aligning sequences with public protein databases. Our platform contained tools like Blast, gene set enrichment analysis, heatmap analysis, sequence extraction, and JBrowse. Analysis revealed co-expression of transcription factors (C2H2, GRAS, NAC) with genes encoding key enzymes in alkaloid biosynthesis. We also showcased the reliability and applicability of our platform using Chalcone synthases (CHS). CONCLUSION: DhuFAP ( www.gzybioinformatics.cn/DhuFAP ) and its suite of tools represent an accessible and invaluable resource for researchers, enabling the exploration of functional information pertaining to D. huoshanense genes. This platform stands poised to facilitate significant biological discoveries in this domain.

MGEGFP: a multi-view graph embedding method for gene function prediction based on adaptive estimation with GCN.

In recent years, a number of computational approaches have been proposed to effectively integrate multiple heterogeneous biological networks, and have shown impressive performance for inferring gene function. However, the previous methods do not fully represent the critical neighborhood relationship between genes during the feature learning process. Furthermore, it is difficult to accurately estimate the contributions of different views for multi-view integration. In this paper, we propose MGEGFP, a multi-view graph embedding method based on adaptive estimation with Graph Convolutional Network (GCN), to learn high-quality gene representations among multiple interaction networks for function prediction. First, we design a dual-channel GCN encoder to disentangle the view-specific information and the consensus pattern across diverse networks. By the aid of disentangled representations, we develop a multi-gate module to adaptively estimate the contributions of different views during each reconstruction process and make full use of the multiplexity advantages, where a diversity preservation constraint is designed to prevent the over-fitting problem. To validate the effectiveness of our model, we conduct experiments on networks from the STRING database for both yeast and human datasets, and compare the performance with seven state-of-the-art methods in five evaluation metrics. Moreover, the ablation study manifests the important contribution of the designed dual-channel encoder, multi-gate module and the diversity preservation constraint in MGEGFP. The experimental results confirm the superiority of our proposed method and suggest that MGEGFP can be a useful tool for gene function prediction.

Root Hairs: An under-explored target for sustainable cereal crop production.

To meet the demands of a rising human population, plant breeders will need to develop improved crop varieties that maximize yield in the face of increasing pressure on crop production. Historically, the optimization of crop root architecture has represented a challenging breeding target due to the inaccessibility of the root systems. Root hairs, single cell projections from the root epidermis, are perhaps the most overlooked component of root architecture traits. Root hairs play a central role in facilitating water, nutrient uptake, and soil cohesion. Current root hair architectures may be suboptimal under future agricultural production regimes, coupled with an increasingly variable climate. Here, we review the genetic control of root hair development in the world's three most important crops: rice, maize and wheat, and highlight conservation of gene function between monocots and the model dicot species Arabidopsis. Advances in genomic techniques including Gene-Editing combined with traditional plant breeding methods have the potential to overcome many inherent issues associated with the design of improved root hair architectures. Ultimately, this will enable detailed characterization of the effects of contrasting root hair morphology strategies on crop yield and resilience, and the development of new varieties better adapted to deliver future food security.

Genes involved in the adhesion and invasion of Arcobacter butzleri.

Arcobacter butzleri is a foodborne pathogen that mainly causes enteritis in humans, but the number of cases of bacteraemia has increased in recent years. However, there is still limited knowledge on the pathogenic mechanisms of this bacterium. To investigate how A. butzleri causes disease, single knockout mutants were constructed in the cadF, ABU_RS00335, ciaB, and flaAB genes, which might be involved in adhesion and invasion properties. These mutants and the isogenic wild-type (WT) were then tested for their ability to adhere and invade human Caco-2 and HT29-MTX cells. The adhesion and invasion of A. butzleri RM4018 strain was also visualized by a Leica CTR 6500 confocal microscope. The adhesion and invasion abilities of mutants lacking the invasion antigen CiaB or a functional flagellum were lower than those of the WTs. However, the extent of the decrease varied depending on the strain and/or cell line. Mutants lacking the fibronectin (FN)-binding protein CadF consistently exhibited reduced abilities, while the inactivation of the other studied FN-binding protein, ABU_RS00335, led to a reduction in only one of the two strains tested. Therefore, the ciaB and flaAB genes appear to be important for A. butzleri adhesion and invasion properties, while cadF appears to be indispensable.

Identification of squalene epoxidase in triterpenes biosynthesis in Poria cocos by molecular docking and CRISPR-Cas9 gene editing.

BACKGROUND: Squalene epoxidase is one of the rate-limiting enzymes in the biosynthetic pathway of membrane sterols and triterpenoids. The enzyme catalyzes the formation of oxidized squalene, which is a common precursor of sterols and triterpenoids. RESULT: In this study, the squalene epoxidase gene (PcSE) was evaluated in Poria cocos. Molecular docking between PcSE and squalene was performed and the active amino acids were identified. The sgRNA were designed based on the active site residues. The effect on triterpene synthesis in P. cocos was consistent with the results from ultra-high-performance liquid chromatography-quadruplex time-of-flight-double mass spectrometry (UHPLC-QTOF-MS/MS) analysis. The results showed that deletion of PcSE inhibited triterpene synthesis. In vivo verification of PcSE function was performed using a PEG-mediated protoplast transformation approach. CONCLUSION: The findings from this study provide a foundation for further studies on heterologous biosynthesis of P. cocos secondary metabolites.

Transcriptome-wide identification of ARF gene family in medicinal plant Polygonatum kingianum and expression analysis of PkARF members in different tissues.

BACKGROUND: Polygonatum kingianum holds significant importance in Traditional Chinese Medicine due to its medicinal properties, characterized by its diverse chemical constituents including polysaccharides, terpenoids, flavonoids, phenols, and phenylpropanoids. The Auxin Response Factor (ARF) is a pivotal transcription factor known for its regulatory role in both primary and secondary metabolite synthesis. However, our understanding of the ARF gene family in P. kingianum remains limited. METHODS AND RESULTS: We employed RNA-Seq to sequence three distinct tissues (leaf, root, and stem) of P. kingianum. The analysis revealed a total of 31,558 differentially expressed genes (DEGs), with 43 species of transcription factors annotated among them. Analyses via gene ontology and the Kyoto Encyclopedia of Genes and Genomes demonstrated that these DEGs were predominantly enriched in metabolic pathways and secondary metabolite biosynthesis. The proposed temporal expression analysis categorized the DEGs into nine clusters, suggesting the same expression trends that may be coordinated in multiple biological processes across the three tissues. Additionally, we conducted screening and expression pattern analysis of the ARF gene family, identifying 12 significantly expressed PkARF genes in P. kingianum roots. This discovery lays the groundwork for investigations into the role of PkARF genes in root growth, development, and secondary metabolism regulation. CONCLUSION: The obtained data and insights serve as a focal point for further research studies, centred on genetic manipulation of growth and secondary metabolism in P. kingianum. Furthermore, these findings contribute to the understanding of functional genomics in P. kingianum, offering valuable genetic resources.

Identification of genomic binding sites and direct target genes for the transcription factor DDIT3/CHOP.

DDIT3 is a tightly regulated basic leucine zipper (bZIP) transcription factor and key regulator in cellular stress responses. It is involved in a variety of pathological conditions and may cause cell cycle block and apoptosis. It is also implicated in differentiation of some specialized cell types and as an oncogene in several types of cancer. DDIT3 was originally believed to act as a dominant-negative inhibitor by forming heterodimers with other bZIP transcription factors, preventing their DNA binding and transactivating functions. DDIT3 has, however, been reported to bind DNA and regulate target genes. Here, we employed ChIP sequencing combined with microarray-based expression analysis to identify direct binding motifs and target genes of DDIT3. The results reveal DDIT3 binding to motifs similar to other bZIP transcription factors, known to form heterodimers with DDIT3. Binding to a class III satellite DNA repeat sequence was also detected. DDIT3 acted as a DNA-binding transcription factor and bound mainly to the promotor region of regulated genes. ChIP sequencing analysis of histone H3K27 methylation and acetylation showed a strong overlap between H3K27-acetylated marks and DDIT3 binding. These results support a role for DDIT3 as a transcriptional regulator of H3K27ac-marked genes in transcriptionally active chromatin.

SNP-based heritability and selection analyses: Improved models and new results.

Complex-trait genetics has advanced dramatically through methods to estimate the heritability tagged by SNPs, both genome-wide and in genomic regions of interest such as those defined by functional annotations. The models underlying many of these analyses are inadequate, and consequently many SNP-heritability results published to date are inaccurate. Here, we review the modelling issues, both for analyses based on individual genotype data and association test statistics, highlighting the role of a low-dimensional model for the heritability of each SNP. We use state-of-art models to present updated results about how heritability is distributed with respect to functional annotations in the human genome, and how it varies with allele frequency, which can reflect purifying selection. Our results give finer detail to the picture that has emerged in recent years of complex trait heritability widely dispersed across the genome. Confounding due to population structure remains a problem that summary statistic analyses cannot reliably overcome. Also see the video abstract here: https://youtu.be/WC2u03V65MQ.

Molecular Mechanism of Different Rooting Capacity between Two Clones of Taxodium hybrid 'Zhongshanshan'.

The conifer Taxodium hybrid 'Zhongshanshan' (T. hybrid 'Zhongshanshan') is characterized by rapid growth, strong stress resistance, and high ornamental value and has significant potential for use in afforestation, landscaping, and wood production. The main method of propagating T. hybrid 'Zhongshanshan' is tender branch cutting, but the cutting rooting abilities of different T. hybrid 'Zhongshanshan' clones differ significantly. To explore the causes of rooting ability differences at a molecular level, we analyzed the transcriptome data of cutting base and root tissues of T. hybrid 'Zhongshanshan 149' with a rooting rate of less than 5% and T. hybrid 'Zhongshanshan 118' with rooting rate greater than 60%, at the developmental time points in this study. The results indicated that differentially expressed genes between the two clones were mainly associated with copper ion binding, peroxidase, and oxidoreductase activity, response to oxidative stress, phenylpropanoid and flavonoid biosynthesis, and plant hormone signal transduction, among others. The expression pattern of ThAP2 was different throughout the development of the adventitive roots of the two clone cuttings. Therefore, this gene was selected for further study. It was shown that ThAP2 was a nuclear-localized transcription factor and demonstrated a positive feedback effect on rooting in transgenic Nicotiana benthamiana cuttings. Thus, the results of this study explain the molecular mechanism of cutting rooting and provide candidate gene resources for developing genetic breeding strategies for optimizing superior clones of T. hybrid 'Zhongshanshan'.

Integrating Multiple Database Resources to Elucidate the Gene Flow in Southeast Asian Pig Populations.

The domestic pig (Sus scrofa) and its subfamilies have experienced long-term and extensive gene flow, particularly in Southeast Asia. Here, we analyzed 236 pigs, focusing on Yunnan indigenous, European commercial, East Asian, and Southeast Asian breeds, using the Pig Genomics Reference Panel (PGRP v1) of Pig Genotype-Tissue Expression (PigGTEx) to investigate gene flow and associated complex traits by integrating multiple database resources. In this study, we discovered evidence of admixtures from European pigs into the genome of Yunnan indigenous pigs. Additionally, we hypothesized that a potential conceptual gene flow route that may have contributed to the genetic composition of the Diannan small-ear pig is a gene exchange from the Vietnamese pig. Based on the most stringent gene introgression scan using the fd statistic, we identified three specific loci on chromosome 8, ranging from 51.65 to 52.45 Mb, which exhibited strong signatures of selection and harbored the NAF1, NPY1R, and NPY5R genes. These genes are associated with complex traits, such as fat mass, immunity, and litter weight, in pigs, as supported by multiple bio-functionalization databases. We utilized multiple databases to explore the potential dynamics of genetic exchange in Southeast Asian pig populations and elucidated specific gene functionalities.

Establishment of a Homologous Silencing System with Intact-Plant Infiltration and Minimized Operation for Studying Gene Function in Herbaceous Peonies.

Gene function verification is a crucial step in studying the molecular mechanisms regulating various plant life activities. However, a stable and efficient homologous genetic transgenic system for herbaceous peonies has not been established. In this study, using virus-induced gene silencing technology (VIGS), a highly efficient homologous transient verification system with distinctive advantages was proposed, which not only achieves true "intact-plant" infiltration but also minimizes the operation. One-year-old roots of the representative species, Paeonia lactiflora Pall., were used as the materials; prechilling (4 °C) treatment for 3-5 weeks was applied as a critical precondition for P. lactiflora to acquire a certain chilling accumulation. A dormancy-related gene named HOMEOBOX PROTEIN 31 (PlHB31), believed to negatively regulate bud endodormancy release (BER), was chosen as the target gene in this study. GFP fluorescence was detected in directly infiltrated and newly developed roots and buds; the transgenic plantlets exhibited remarkably earlier budbreak, and PlHB31 was significantly downregulated in silenced plantlets. This study established a homologous transient silencing system featuring intact-plant infiltration and minimized manipulation for gene function research, and also offers technical support and serves as a theoretical basis for gene function discovery in numerous other geophytes.

Identification of Gene-Allele System Conferring Alkali-Tolerance at Seedling Stage in Northeast China Soybean Germplasm.

Salinization of cultivated soils may result in either high salt levels or alkaline conditions, both of which stress crops and reduce performance. We sampled genotypes included in the Northeast China soybean germplasm population (NECSGP) to identify possible genes that affect tolerance to alkaline soil conditions. In this study, 361 soybean accessions collected in Northeast China were tested under 220 mM NaHCO3:Na2CO3 = 9:1 (pH = 9.8) to evaluate the alkali-tolerance (ATI) at the seedling stage in Mudanjiang, Heilongjiang, China. The restricted two-stage multi-locus model genome-wide association study (RTM-GWAS) with gene-allele sequences as markers (6503 GASMs) based on simplified genome resequencing (RAD-sequencing) was accomplished. From this analysis, 132 main effect candidate genes with 359 alleles and 35 Gene × Environment genes with 103 alleles were identified, explaining 90.93% and 2.80% of the seedling alkali-tolerance phenotypic variation, respectively. Genetic variability of ATI in NECSGP was observed primarily within subpopulations, especially in ecoregion B, from which 80% of ATI-tolerant accessions were screened out. The biological functions of 132 candidate genes were classified into eight functional categories (defense response, substance transport, regulation, metabolism-related, substance synthesis, biological process, plant development, and unknown function). From the ATI gene-allele system, six key genes-alleles were identified as starting points for further study on understanding the ATI gene network.

Effects of exogenous N-acyl homoserine lactones (AHLs) on methanogenic activities and microbial community differences during anaerobic digestion.

N-acyl homoserine lactones (AHLs) function as signaling molecules influencing microbial community dynamics. This study investigates the impact of exogenously applied AHLs on methane production during waste-activated sludge (WAS) anaerobic digestion (AD). Nine AHL types, ranging from 10-4 to 10 µg/g VSS, were applied, comparing microbial community composition under optimal AHL concentrations. Firmicutes, Bacteroidetes, Chloroflexi, and Proteobacteria were identified in anaerobic digesters with C4-HSL, C6-HSL, and C8-HSL. Compared to the control, Halobacterota increased by 19.25%, 20.87%, and 9.33% with C7-HSL, C10-HSL, and C12-HSL. Exogenous C7-HSL enhanced the relative abundance of Methanosarcina, Romboutsia, Sedimentibacter, Proteiniclasticum, Christensenellaceae_R-7_group. C10-HSL increased Methanosarcina abundance. C4-HSL, C6-HSL, C8-HSL, C10-HSL, and C12-HSL showed potential to increase unclassified_Firmicutes. Functional Annotation of Prokaryotic Taxa (FAPROTAX) predicted AHLs' impact on related functional genes, providing insights into their role in AD methanogenesis regulation. This study aimed to enhance the understanding of the influence of different types of exogenous AHLs on AD and provide technical support for regulating the methanogenesis efficiency of AD by exogenous AHLs.

Role of grapevine SEPALLATA-related MADS-box gene VvMADS39 in flower and ovule development.

Seedlessness is one of the most important breeding goals for table grapes; thus, understanding the molecular genetic regulation of seed development and abortion is critical for the development of seedless cultivars. In the present study, we characterized VvMADS39, a class E MADS-box gene of grapevine (Vitis vinifera) orthologous to Arabidopsis SEP2. Heterologous overexpression of VvMADS39 in tomato reduced the fruit and seed size and seed number. Targeted mutagenesis of the homologous SlMADS39 in tomato induced various floral and fruit defects. It could reasonable to suppose that active VvMADS39 expression in "Thompson Seedless" may restrict cellular expansion, resulting in the development of smaller fruits and seeds, VvMADS39 may play a role in the regulation of ovule development in grapevine and contributes to seedless fruit formation. In contrast, VvMADS39 suppression in "Red Globe" was associated with enhanced histone H3 lysine 27 trimethylation in the promoter region of VvMADS39, allowing normal ovule and fruit development; Meanwhile, VvMADS39 interacts with VvAGAMOUS, and the activity of the VvMADS39-VvAGAMOUS dimer to induce integument development requires the activation and maintenance of VvINO expression. The synergistic cooperation between VvMADS39 and related proteins plays an important role in maintaining floral meristem characteristics, and fruit and ovule development.

SvSTL1 in the large subunit family of ribonucleotide reductases plays a major role in chloroplast development of Setaria viridis.

Ribonucleotide reductases (RNRs) are essential enzymes in DNA synthesis. However, little is known about the RNRs in plants. Here, we identified a svstl1 mutant from the self-created ethyl methanesulfonate (EMS) mutant library of Setaria viridis. The mutant leaves exhibited a bleaching phenotype at the heading stage. Paraffin section analysis showed the destruction of the C4 Kranz anatomy. Transmission electron microscopy results further demonstrated the severely disturbed development of some chloroplasts. MutMap analysis revealed that the SvSTL1 gene is the primary candidate, encoding a large subunit of RNRs. Complementation experiments confirmed that SvSTL1 is responsible for the phenotype of svstl1. There are two additional RNR large subunit homologs in S. viridis, SvSTL2 and SvSTL3. To further understand the functions of these three RNR large subunit genes, a series of mutants were generated via CRISPR/Cas9 technology. In striking contrast to the finding that all three SvSTLs interact with the RNR small subunit, the phenotype varied along with the copies of chloroplast genome among different svstl single mutants: the svstl1 mutant exhibited pronounced chloroplast development and significantly fewer copies of the chloroplast genome than the svstl2 or svstl3 single mutants. These results suggested that SvSTL1 plays a major role in the optimal function of RNRs and is essential for chloroplast development. Furthermore, through the analysis of double and triple mutants, the study provides new insights into the finely tuned coordination among SvSTLs to maintain normal chloroplast development in the emerging C4 model plant S. viridis.

Rapid Gene Evolution in an Ancient Post-transcriptional and Translational Regulatory System Compensates for Meiotic X Chromosomal Inactivation.

It is conventionally assumed that conserved pathways evolve slowly with little participation of gene evolution. Nevertheless, it has been recently observed that young genes can take over fundamental functions in essential biological processes, for example, development and reproduction. It is unclear how newly duplicated genes are integrated into ancestral networks and reshape the conserved pathways of important functions. Here, we investigated origination and function of two autosomal genes that evolved recently in Drosophila: Poseidon and Zeus, which were created by RNA-based duplications from the X-linked CAF40, a subunit of the conserved CCR4-NOT deadenylase complex involved in posttranscriptional and translational regulation. Knockdown and knockout assays show that the two genes quickly evolved critically important functions in viability and male fertility. Moreover, our transcriptome analysis demonstrates that the three genes have a broad and distinct effect in the expression of hundreds of genes, with almost half of the differentially expressed genes being perturbed exclusively by one paralog, but not the others. Co-immunoprecipitation and tethering assays show that the CAF40 paralog Poseidon maintains the ability to interact with the CCR4-NOT deadenylase complex and might act in posttranscriptional mRNA regulation. The rapid gene evolution in the ancient posttranscriptional and translational regulatory system may be driven by evolution of sex chromosomes to compensate for the meiotic X chromosomal inactivation (MXCI) in Drosophila.