Nonsense mediated mrna decay

Nebulin, a critical protein of the skeletal muscle thin filament, plays important roles in physiological processes such as regulating thin filament length (TFL), cross-bridge cycling, and myofibril alignment. Pathogenic variants in the nebulin gene (NEB) cause NEB-based nemaline myopathy (NEM2), a genetically heterogeneous disorder characterized by hypotonia and muscle weakness, currently lacking curative therapies. In this study, we examined a cohort of ten NEM2 patients, each with unique pathogenic variants, aiming to understand their impact on mRNA, protein, and functional levels...

Post-transcriptional mRNA regulation shapes gene expression, yet how cis-elements and mRNA translation interface to regulate mRNA stability is poorly understood. We find that the strength of translation initiation, upstream open reading frame (uORF) content, codon optimality, AU-rich elements, microRNA binding sites, and open reading frame (ORF) length function combinatorially to regulate mRNA stability. Machine-learning analysis identifies ORF length as the most important conserved feature regulating mRNA decay...

It is known that more than 10% of genetic diseases are caused by a mutation in protein-coding mRNA (premature termination codon; PTC). mRNAs with an early stop codon are degraded by the cellular surveillance process known as nonsense-mediated mRNA decay (NMD), which prevents the synthesis of C-terminally truncated proteins. Up-frameshift-1 (UPF1) has been reported to be involved in the downregulation of various cancers, and low expression of UPF1 was shown to correlate with poor prognosis. It is known that UPF1 is a master regulator of nonsense-mediated mRNA decay (NMD)...

The molecular basis of mullerian aplasia, also known as Mayer-Rokitansky-Kuster Hauser (MRKH) or congenital absence of the uterus and vagina, is largely unknown. We applied a multifaceted genetic approach to studying the pathogenesis of MRKH including exome sequencing of trios and duos, genome sequencing of families, qPCR, RT-PCR, and Sanger sequencing to detect intragenic deletions, insertions, splice variants, single nucleotide variants, and rearrangements in 132 persons with MRKH. We identified two heterozygous variants in ZNHIT3 localized to a commonly involved CNV region at chromosome 17q12 in two different families with MRKH...

Townes-Brocks syndrome (TBS) is an autosomal dominant disorder characterised by the triad of anorectal, thumb, and ear malformations. It may also be accompanied by defects in kidney, heart, eyes, hearing, and feet. TBS has been demonstrated to result from heterozygous variants in the SALL1 gene, which encodes zinc finger protein believed to function as a transcriptional repressor. The clinical characteristics of an atypical TBS phenotype patient from a Chinese family are described, with predominant manifestations including external ear dysplasia, unilateral renal hypoplasia with mild renal dysfunction, and hearing impairment...

Pyruvate kinase (PK) deficiency is a rare autosomal recessive disorder characterized by chronic hemolytic anemia of variable severity. Nine Polish patients with severe hemolytic anemia but normal PK activity were found to carry mutations in the PKLR gene encoding PK, five already known ones and one novel (c.178C > T). We characterized two of the known variants by molecular modeling (c.1058delAAG) and minigene splicing analysis (c.101-1G > A). The former gives a partially destabilized PK tetramer, likely of suboptimal activity, and the c...

We encountered a Chinese girl with pseudohypoparathyroidism type 1A (PHP1A) and her mother with pseudopseudohypoparathyroidism (PPHP). Sequencing analysis of GNAS -Gsα revealed a heterozygous c.212+2T>C variant (NM_000516.4) affecting the canonical splice donor site of intron 2 in the girl and her mother. RT-PCR performed on mRNA samples obtained from cycloheximide-treated and cycloheximide-untreated lymphoblastoid cell lines of this girl revealed the utilization of an alternative splice donor site at 33-34 bp from the boundary between exon 2 and intron 2 and the production of an aberrant mRNA with a retention of a 32 bp intronic sequence between exon 2 and exon 3 (p...

FOXP1 encodes a transcription factor involved in tissue regulation and cell-type-specific functions. Haploinsufficiency of FOXP1 is associated with a neurodevelopmental disorder: autosomal dominant mental retardation with language impairment with or without autistic features. More recently, heterozygous FOXP1 variants have also been shown to cause a variety of structural birth defects including central nervous system (CNS) anomalies, congenital heart defects, congenital anomalies of the kidney and urinary tract, cryptorchidism, and hypospadias...

Translating genetic findings for neurodevelopmental and psychiatric disorders (NPD) into actionable disease biology would benefit from large-scale and unbiased functional studies of NPD genes. Leveraging the cytosine base editing (CBE) system, here we developed a pipeline for clonal loss-of-function (LoF) allele mutagenesis in human induced pluripotent stem cells (hiPSCs) by introducing premature stop-codons (iSTOP) that lead to mRNA nonsense-mediated-decay (NMD) or protein truncation. We tested the pipeline for 23 NPD genes on 3 hiPSC lines and achieved highly reproducible, efficient iSTOP editing in 22 NPD genes...

INTRODUCTION/AIMS: GNE myopathy is a rare autosomal recessive disorder caused by pathogenic variants in the GNE gene, which is essential for the sialic acid biosynthesis pathway. Although over 300 GNE variants have been reported, some patients remain undiagnosed with monoallelic pathogenic variants. This study aims to analyze the entire GNE genomic region to identify novel pathogenic variants. METHODS: Patients with clinically compatible GNE myopathy and monoallelic pathogenic variants in the GNE gene were enrolled...

Nonsense mutations that generate a premature termination codon (PTC) can induce both the accelerated degradation of mutated mRNA compared with the wild type version of the mRNA or the production of a truncated protein. One of the considered therapeutic strategies to bypass PTCs is their "readthrough" based on small-molecule drugs. These molecules promote the incorporation of a near-cognate tRNA at the PTC position through the native polypeptide chain. In this review, we detailed the various existing strategies organized according to pharmacological molecule types through their different mechanisms...

Retinitis pigmentosa 11 is an untreatable, dominantly inherited retinal disease caused by heterozygous mutations in pre-mRNA processing factor 31 PRPF31 . The expression level of PRPF31 is linked to incomplete penetrance in affected families; mutation carriers with higher PRPF31 expression can remain asymptomatic. The current study explores an antisense oligonucleotide exon skipping strategy to treat RP11 caused by truncating mutations within PRPF31 exon 12 since it does not appear to encode any domains essential for PRPF31 protein function...

mRNAs containing premature stop codons are responsible for various genetic diseases as well as cancers. The truncated proteins synthesized from these aberrant mRNAs are seldom detected due to the nonsense-mediated mRNA decay (NMD) pathway. Such a surveillance mechanism detects most of these aberrant mRNAs and rapidly destroys them from the pool of mRNAs. Here, we implemented chemical cross-linking mass spectrometry (CLMS) techniques to trace novel biology consisting of protein-protein interactions (PPIs) within the NMD machinery...

BACKGROUND: Targeting long non-coding RNAs (LncRNAs) is a novel and promising approach in cancer therapy. In our previous study, we investigated the effects of ailanthone (aila), the main active compound derived from the stem barks of Ailanthus altissima (Mill.) Swingle, on the growth of non-small cell lung cancer (NSCLC) cells. Although we observed significant inhibition of NSCLC cell growth of aila, the underlying mechanisms involving LncRNAs, specifically LncRNA growth arrest specific 5 (GAS5), remain largely unknown...

KBG syndrome is a rare autosomal dominant condition characterized by multisystem developmental disorder, primarily caused by loss-of-function variants in ankyrin repeat domain-containing protein 11 (ANKRD11). Approximately 80 % of ANKRD11 variants associated with KBG syndrome, are frameshift and nonsense variants. Current insight into the pathogenesis of KBG syndrome resulting from ANKRD11 truncating variants remains limited. Here, we presented two members from a non-consanguineous Chinese pedigree both exhibiting characteristics fitting the KBG syndrome-associated phenotypic spectrum...

Translation of mRNAs encoding integral membrane proteins or secreted proteins occurs on the surface of the endoplasmic reticulum (ER). When a nascent signal peptide is synthesized from the mRNAs, the ribosome-nascent chain complex (RNC) is recognized by the signal recognition particle (SRP) and then transported to the surface of the ER. The appropriate targeting of the RNC-SRP complex to the ER is monitored by a quality control pathway, a nuclear cap-binding complex (CBC)-ensured translational repression of RNC-SRP (CENTRE)...

The transcription factor RUNX1 is a master regulator of hematopoiesis and is frequently mutated in myeloid malignancies. Mutations in its runt homology domain (RHD) frequently disrupt DNA binding and result in loss of RUNX1 function. However, it is not clearly understood how other RUNX1 mutations contribute to disease development. Here, we characterize RUNX1 mutations outside of the RHD. Our analysis of patient datasets revealed that mutations within the C-terminus frequently occur in hematopoietic disorders...

Deposition of the exon junction complex (EJC) upstream of exon-exon junctions helps maintain transcriptome integrity by preventing spurious re-splicing events in already spliced mRNAs. Here we investigate the importance of EJC for the correct splicing of the 2.2-megabase-long human DMD pre-mRNA, which encodes dystrophin, an essential protein involved in cytoskeletal organization and cell signaling. Using targeted RNA-seq, we show that knock-down of the eIF4A3 and Y14 core components of EJC in a human muscle cell line causes an accumulation of mis-splicing events clustered towards the 3' end of the DMD transcript (Dp427m)...

Integrin receptors for the extracellular matrix activate intracellular signaling pathways that are critical for tissue development, homeostasis, and regeneration/repair, and their loss or dysregulation contributes to many developmental defects and tissue pathologies. This review will focus on tissue remodeling roles for integrin α3β1, a receptor for laminins found in the basement membranes that underlie epithelial cell layers. As a paradigm, we will discuss literature that supports a role for α3β1 in promoting ability of epidermal keratinocytes to modify their tissue microenvironment during skin development, wound healing or tumorigenesis...

A comprehensive understanding of molecular changes during brain aging is essential to mitigate cognitive decline and delay neurodegenerative diseases. The interpretation of mRNA alterations during brain aging is influenced by the health and age of the animal cohorts studied. Here, we carefully consider these factors and provide an in-depth investigation of mRNA splicing and dynamics in the aging mouse brain, combining short- and long-read sequencing technologies with extensive bioinformatic analyses. Our findings encompass a spectrum of age-related changes, including differences in isoform usage, decreased mRNA dynamics and a module showing increased expression of neuronal genes...