Mechanism of U6 snRNA oligouridylation by human TUT1

ILP1 and NTR1 affect the stability of U6 snRNA during spliceosome complex disassembly in Arabidopsis

U6 snRNA is one of the uridine-rich non-coding RNAs, abundant and stable in various cells, function as core particles in the intron-lariat spliceosome (ILS) complex. The Increased Level of Polyploidy1-1D (ILP1) and NTC-related protein 1 (NTR1), two conserved disassembly factors of the ILS complex, facilitates the disintegration of the ILS complex after completing intron splicing. The functional impairment of ILP1 and NTR1 lead to increased U6 levels, while other snRNAs comprising the ILS complex remained unaffected. We revealed that ILP1 and NTR1 had no impact on the transcription, 3' end phosphate structure or oligo(U) tail of U6 snRNA. Moreover, we uncovered that the mutation of ILP1 and NTR1 resulted in the accumulation of ILS complexes, impeding the dissociation of U6 from splicing factors, leading to an extended half-life of U6 and ultimately causing an elevation in U6 snRNA levels. Our findings broaden the understanding of the functions of ILS disassembly factors ILP1 and NTR1, and providing insights into the dynamic disassembly between U6 and ILS.

Regulation of the poly(A) Polymerase Star-PAP by a Nuclear Phosphoinositide Signalosome

Star-PAP is a noncanonical poly(A) polymerase that controls gene expression. Star-PAP was previously reported to bind the phosphatidylinositol 4-phosphate 5-kinase PIPKI⍺ and its product phosphatidylinositol 4,5-bisphosphate, which regulate Star-PAP poly(A) polymerase activity and expression of specific genes. Recent studies have revealed a nuclear PI signaling pathway in which the PI transfer proteins PITP⍺/β, PI kinases and phosphatases bind p53 to sequentially modify protein-linked phosphatidylinositol phosphates and regulate its function. Here we demonstrate that multiple phosphoinositides, including phosphatidylinositol 4-monophosphate and phosphatidylinositol 3,4,5-trisphosphate are also coupled to Star-PAP in response to stress. This is initiated by PITP⍺/β binding to Star-PAP, while the Star-PAP-linked phosphoinositides are modified by PI4KII⍺, PIPKI⍺, IPMK, and PTEN recruited to Star- PAP. The phosphoinositide coupling enhances the association of the small heat shock proteins HSP27/⍺B-crystallin with Star-PAP. Knockdown of the PITPs, kinases, or HSP27 reduce the expression of Star-PAP targets. Our results demonstrate that the PITPs generate Star-PAP-PIPn complexes that are then modified by PI kinases/phosphatases and small heat shock proteins that regulate the linked phosphoinositide phosphorylation and Star-PAP activity in response to stress.

Spliceosomal snRNAs, the Essential Players in pre-mRNA Processing in Eukaryotic Nucleus: From Biogenesis to Functions and Spatiotemporal Characteristics

Spliceosomal small nuclear RNAs (snRNAs) are a fundamental class of non-coding small RNAs abundant in the nucleoplasm of eukaryotic cells, playing a crucial role in splicing precursor messenger RNAs (pre-mRNAs). They are transcribed by DNA-dependent RNA polymerase II (Pol II) or III (Pol III), and undergo subsequent processing and 3' end cleavage to become mature snRNAs. Numerous protein factors are involved in the transcription initiation, elongation, termination, splicing, cellular localization, and terminal modification processes of snRNAs. The transcription and processing of snRNAs are regulated spatiotemporally by various mechanisms, and the homeostatic balance of snRNAs within cells is of great significance for the growth and development of organisms. snRNAs assemble with specific accessory proteins to form small nuclear ribonucleoprotein particles (snRNPs) that are the basal components of spliceosomes responsible for pre-mRNA maturation. This article provides an overview of the biological functions, biosynthesis, terminal structure, and tissue-specific regulation of snRNAs.

Genome-wide association study identifies novel susceptible loci and evaluation of polygenic risk score for chronic obstructive pulmonary disease in a Taiwanese population

BACKGROUND

Chronic Obstructive Pulmonary Disease (COPD) describes a group of progressive lung diseases causing breathing difficulties. While COPD development typically involves a complex interplay between genetic and environmental factors, genetics play a role in disease susceptibility. This study used genome-wide association studies (GWAS) and polygenic risk score (PRS) to elucidate the genetic basis for COPD in Taiwanese patients.

RESULTS

GWAS was performed on a Taiwanese COPD case-control cohort with a sample size of 5,442 cases and 17,681 controls. Additionally, the PRS was calculated and assessed in our target groups. GWAS results indicate that although there were no single nucleotide polymorphisms (SNPs) of genome-wide significance, prominent COPD susceptibility loci on or nearby genes such as WWTR1, EXT1, INTU, MAP3K7CL, MAMDC2, BZW1/CLK1, LINC01197, LINC01894, and CFAP95 (C9orf135) were identified, which had not been reported in previous studies. Thirteen susceptibility loci, such as CHRNA4, AFAP1, and DTWD1, previously reported in other populations were replicated and confirmed to be associated with COPD in Taiwanese populations. The PRS was determined in the target groups using the summary statistics from our base group, yielding an effective association with COPD (odds ratio [OR] 1.09, 95% confidence interval [CI] 1.02-1.17, p = 0.011). Furthermore, replication a previous lung function trait PRS model in our target group, showed a significant association of COPD susceptibility with PRS of Forced Expiratory Volume in one second (FEV1)/Forced Vital Capacity (FCV) (OR 0.89, 95% CI 0.83-0.95, p = 0.001).

CONCLUSIONS

Novel COPD-related genes were identified in the studied Taiwanese population. The PRS model, based on COPD or lung function traits, enables disease risk estimation and enhances prediction before suffering. These results offer new perspectives on the genetics of COPD and serve as a basis for future research.

Identification and Expression Analysis of the Nucleotidyl Transferase Protein (NTP) Family in Soybean (Glycine max) under Various Abiotic Stresses

Nucleotidyl transferases (NTPs) are common transferases in eukaryotes and play a crucial role in nucleotide modifications at the 3' end of RNA. In plants, NTPs can regulate RNA stability by influencing 3' end modifications, which in turn affect plant growth, development, stress responses, and disease resistance. Although the functions of NTP family members have been extensively studied in Arabidopsis, rice, and maize, there is limited knowledge about NTP genes in soybeans. In this study, we identified 16 members of the NTP family in soybeans, including two subfamilies (G1 and G2) with distinct secondary structures, conserved motifs, and domain distributions at the protein level. Evolutionary analysis of genes in the NTP family across multiple species and gene collinearity analysis revealed a relatively conserved evolutionary pattern. Analysis of the tertiary structure of the proteins showed that NTPs have three conserved aspartic acids that bind together to form a possible active site. Tissue-specific expression analysis indicated that some NTP genes exhibit tissue-specific expression, likely due to their specific functions. Stress expression analysis showed significant differences in the expression levels of NTP genes under high salt, drought, and cold stress. Additionally, RNA-seq analysis of soybean plants subjected to salt and drought stress further confirmed the association of soybean NTP genes with abiotic stress responses. Subcellular localization experiments revealed that GmNTP2 and GmNTP14, which likely have similar functions to HESO1 and URT1, are located in the nucleus. These research findings provide a foundation for further investigations into the functions of NTP family genes in soybeans.