Rapid meiotic prophase chromosome movements in Arabidopsis thaliana are linked to essential reorganization at the nuclear envelope.

Meiotic rapid prophase chromosome movements (RPMs) require connections between the chromosomes and the cytoskeleton, involving SUN (Sad1/UNC-84)-domain-containing proteins at the inner nuclear envelope (NE). RPMs remain significantly understudied in plants, with respect to their importance in the regulation of meiosis. Here, we demonstrate that Arabidopsis thaliana meiotic centromeres undergo rapid (up to 500 nm/s) and uncoordinated movements during the zygotene and pachytene stages. These centromere movements are not affected by altered chromosome organization and recombination but are abolished in the double mutant sun1 sun2. We also document the changes in chromosome dynamics and nucleus organization during the transition from leptotene to zygotene, including telomere attachment to SUN-enriched NE domains, bouquet formation, and nucleolus displacement, all of which were defective in sun1 sun2. These results establish A. thaliana as a model species for studying the functional implications of meiotic RPMs and demonstrate the mechanistic conservation of telomere-led RPMs in plants.

NOP2 facilitates EZH2-mediated epithelial-mesenchymal transition by enhancing EZH2 mRNA stability via m5C methylation in lung cancer progression.

NOP2, a member of the NOL1/NOP2/SUN domain (NSUN) family, is responsible for catalyzing the posttranscriptional modification of RNA through 5-methylcytosine (m5C). Dysregulation of m5C modification has been linked to the pathogenesis of various malignant tumors. Herein, we investigated the expression of NOP2 in lung adenocarcinoma (LUAD) tissues and cells, and found that it was significantly upregulated. Moreover, lentivirus-mediated overexpression of NOP2 in vitro resulted in enhanced migration and invasion capabilities of lung cancer cells, while in vivo experiments demonstrated its ability to promote the growth and metastasis of xenograft tumors. In contrast, knockdown of NOP2 effectively inhibited the growth and metastasis of lung cancer cells. RNA-sequencing was conducted to ascertain the downstream targets of NOP2, and the findings revealed a significant upregulation in EZH2 mRNA expression upon overexpression of NOP2. Subsequent validation experiments demonstrated that NOP2 exerted an m5C-dependent influence on the stability of EZH2 mRNA. Additionally, our investigations revealed a co-regulatory relationship between NOP2 and the m5C reader protein ALYREF in modulating the stability of EZH2 mRNA. Notably, the NOP2/EZH2 axis facilitated the malignant phenotype of lung cancer cells by inducing epithelial-mesenchymal transition (EMT) both in vitro and in vivo. Mechanistically, ChIP analysis proved that EZH2 counteracted the impact of NOP2 on the occupancy capacity of EZH2 and H3K27me3 in the promoter regions of E-cadherin, a gene crucial for regulating EMT. In a word, our research highlights the significant role of NOP2 in LUAD and offers novel mechanistic insights into the NOP2/ALYREF/EZH2 axis, which holds promise as a potential target for lung cancer therapy.

WRN inhibition leads to its chromatin-associated degradation via the PIAS4-RNF4-p97/VCP axis.

Synthetic lethality provides an attractive strategy for developing targeted cancer therapies. For example, cancer cells with high levels of microsatellite instability (MSI-H) are dependent on the Werner (WRN) helicase for survival. However, the mechanisms that regulate WRN spatiotemporal dynamics remain poorly understood. Here, we used single-molecule tracking (SMT) in combination with a WRN inhibitor to examine WRN dynamics within the nuclei of living cancer cells. WRN inhibition traps the helicase on chromatin, requiring p97/VCP for extraction and proteasomal degradation in a MSI-H dependent manner. Using a phenotypic screen, we identify the PIAS4-RNF4 axis as the pathway responsible for WRN degradation. Finally, we show that co-inhibition of WRN and SUMOylation has an additive toxic effect in MSI-H cells and confirm the in vivo activity of WRN inhibition using an MSI-H mouse xenograft model. This work elucidates a regulatory mechanism for WRN that may facilitate identification of new therapeutic modalities, and highlights the use of SMT as a tool for drug discovery and mechanism-of-action studies.

[Research Progress on Pathogenesis and Treatment of NUT Carcinoma].

NUT carcinoma (nuclear protein in testis carcinoma) is a rare and highly invasive malignant tumor, which is most common in midline organs and lungs. The characteristic genetic change of NUT carcinoma is the rearrangement of NUT middle carcinoma family member 1 (NUTM1) gene. In this article, we will review the pathogenic mechanism of its most common fusion form, bromodomaincontaining protein 4 (BRD4)-NUTM1 fusion gene, and the progress in the research and development of targeting drugs.
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Effect of ZIC2 on immune infiltration and ceRNA axis regulation in lung adenocarcinoma via bioinformatics and experimental studies.

OBJECTIVE: This study aimed to conclude the effect and mechanism of ZIC2 on immune infiltration in lung adenocarcinoma (LUAD). METHODS: Expression of ZIC2 in several kinds of normal tissues of TCGA data was analyzed and its correlation with the baseline characteristic of LUAD patients were analyzed. The immune infiltration analysis of LUAD patients was performed by CIBERSORT algorithm. The correlation analysis between ZIC2 and immune cell composition was performed. Additionally, the potential upstream regulatory mechanisms of ZIC2 were predicted to identify the possible miRNAs and lncRNAs that regulated ZIC2 in LUAD. In vitro and in vivo experiments were also conducted to confirm the potential effect of ZIC2 on cell proliferation and invasion ability of LUAD cells. RESULTS: ZIC2 expression was decreased in various normal tissues, but increased in multiple tumors, including LUAD, and correlated with the prognosis of LUAD patients. Enrichment by GO and KEGG suggested the possible association of ZIC2 with cell cycle and p53 signal pathway. ZIC2 expression was significantly correlated with T cells CD4 memory resting, Macrophages M1, and plasma cells, indicating that dysregulated ZIC2 expression in LUAD may directly influence immune infiltration. ZIC2 might be regulated by several different lncRNA-mediated ceRNA mechanisms. In vitro experiments validated the promotive effect of ZIC2 on cell viability and invasion ability of LUAD cells. In vivo experiments validated ZIC2 can accelerate tumor growth in nude mouse. CONCLUSION: ZIC2 regulated by different lncRNA-mediated ceRNA mechanisms may play a critical regulatory role in LUAD through mediating the composition of immune cells in tumor microenvironment.

NDC80/HEC1 promotes macrophage polarization and predicts glioma prognosis via single-cell RNA-seq and in vitro experiment.

INTRODUCTION: Glioma is the most frequent and lethal form of primary brain tumor. The molecular mechanism of oncogenesis and progression of glioma still remains unclear, rendering the therapeutic effect of conventional radiotherapy, chemotherapy, and surgical resection insufficient. In this study, we sought to explore the function of HEC1 (highly expressed in cancer 1) in glioma; a component of the NDC80 complex in glioma is crucial in the regulation of kinetochore. METHODS: Bulk RNA and scRNA-seq analyses were used to infer HEC1 function, and in vitro experiments validated its function. RESULTS: HEC1 overexpression was observed in glioma and was indicative of poor prognosis and malignant clinical features, which was confirmed in human glioma tissues. High HEC1 expression was correlated with more active cell cycle, DNA-associated activities, and the formation of immunosuppressive tumor microenvironment, including interaction with immune cells, and correlated strongly with infiltrating immune cells and enhanced expression of immune checkpoints. In vitro experiments and RNA-seq further confirmed the role of HEC1 in promoting cell proliferation, and the expression of DNA replication and repair pathways in glioma. Coculture assay confirmed that HEC1 promotes microglial migration and the transformation of M1 phenotype macrophage to M2 phenotype. CONCLUSION: Altogether, these findings demonstrate that HEC1 may be a potential prognostic marker and an immunotherapeutic target in glioma.

Transcriptional Repressor BCL11A in Erythroid Cells.

BCL11A, a zinc finger repressor, is a stage-specific transcription factor that controls the switch from fetal (HbF, α2γ2) to adult (HbA, α2ß2) hemoglobin in erythroid cells. While BCL11A was known as a factor critical for B-lymphoid cell development, its relationship to erythroid cells and HbF arose through genome-wide association studies (GWAS). Subsequent work validated its role as a silencer of γ-globin gene expression in cultured cells and mice. Erythroid-specific loss of BCL11A rescues the phenotype of engineered sickle cell disease (SCD) mice, thereby suggesting that downregulation of BCL11A expression might be beneficial in patients with SCD and ß-thalassemia. Common genetic variation in GWAS resides in an erythroid-specific enhancer within the BCL11A gene that is required for its own expression. CRISPR/Cas9 gene editing of the enhancer revealed a GATA-binding site that confers a large portion of its regulatory function. Disruption of the GATA site leads to robust HbF reactivation. Advancement of a guide RNA targeting the GATA-binding site in clinical trials has recently led to approval of first-in-man use of ex vivo CRISPR editing of hematopoietic stem/progenitor cells (HSPCs) as therapy of SCD and ß-thalassemia. Future challenges include expanding access and infrastructure for delivery of genetic therapy to eligible patients, reducing potential toxicity and costs, exploring prospects for in vivo targeting of hematopoietic stem cells (HSCs), and developing small molecule drugs that impair function of BCL11A protein as an alternative option.

The kinase Rio1 and a ribosome collision-dependent decay pathway survey the integrity of 18S rRNA cleavage.

The 18S rRNA sequence is highly conserved, particularly at its 3'-end, which is formed by the endonuclease Nob1. How Nob1 identifies its target sequence is not known, and in vitro experiments have shown Nob1 to be error-prone. Moreover, the sequence around the 3'-end is degenerate with similar sites nearby. Here, we used yeast genetics, biochemistry, and next-generation sequencing to investigate a role for the ATPase Rio1 in monitoring the accuracy of the 18S rRNA 3'-end. We demonstrate that Nob1 can miscleave its rRNA substrate and that miscleaved rRNA accumulates upon bypassing the Rio1-mediated quality control (QC) step, but not in healthy cells with intact QC mechanisms. Mechanistically, we show that Rio1 binding to miscleaved rRNA is weaker than its binding to accurately processed 18S rRNA. Accordingly, excess Rio1 results in accumulation of miscleaved rRNA. Ribosomes containing miscleaved rRNA can translate, albeit more slowly, thereby inviting collisions with trailing ribosomes. These collisions result in degradation of the defective ribosomes utilizing parts of the machinery for mRNA QC. Altogether, the data support a model in which Rio1 inspects the 3'-end of the nascent 18S rRNA to prevent miscleaved 18S rRNA-containing ribosomes from erroneously engaging in translation, where they induce ribosome collisions. The data also demonstrate how ribosome collisions purify cells of altered ribosomes with different functionalities, with important implications for the concept of ribosome heterogeneity.

N6-methyladenosine-modified ALDH9A1 modulates lipid accumulation and tumor progression in clear cell renal cell carcinoma through the NPM1/IQGAP2/AKT signaling pathway.

Aldehyde dehydrogenases superfamily (ALDHs), which are ubiquitously present in various organisms with diverse subcellular localizations, play a crucial role in regulating malignant tumor progression; Nevertheless, their involvement in clear cell renal cell carcinoma (ccRCC) has not been elucidated. In this study, we performed comprehensive bioinformatics analyses on the 19 ALDHs genes, and identified ALDH9A1 as a key contributor in ccRCC. Expression patterns and clinical relevance of ALDH9A1 were determined using bioinformatics analyses, real-time PCR, western blotting, and immunohistochemistry. To explore the underlying mechanism behind the tumor suppressor role of ALDH9A1, RNA sequencing, methylated RNA immunoprecipitation, luciferase reporter assay, mass spectroscopy, immunoprecipitation, mutational studies and immunofluorescence were employed. The impact of ALDH9A1 in ccRCC progression and metabolic programming was assessed through both in vitro and in vivo. Here, this study revealed ALDH9A1 as a tumor suppressor gene in ccRCC. The fat mass and obesity associated protein (FTO) was identified as a demethylase for ALDH9A1 mRNA, resulting in its reduced stability and expression levels in ccRCC. Functional experiments demonstrated that the deficiency of ALDH9A1 in ccRCC promoted tumor proliferation, invasion, migration and lipid accumulation. Mechanistic insights illustrated that the diminished levels of ALDH9A1 resulted in the failure to sequester nucleophosmin 1 (NPM1) within cytoplasm, thereby suppressing the transcription of IQ motif containing the GTPase-activating protein 2 (IQGAP2), subsequently activating the AKT-mTOR signaling, ultimately fostering tumor progression and lipid accumulation. In conclusion, the present study highlights the robust prognostic significance of ALDH9A1 and delivers a comprehensive understanding of ALDH9A1-NPM1-IQGAP2-AKT axis in ccRCC. These findings established a solid research foundation for novel therapeutic strategies for ccRCC patients.

Expanding the Spectrum of NUTM1 -Rearranged Sarcoma : A Clinicopathologic and Molecular Genetic Study of 8 Cases.

Apart from the lethal midline carcinoma (NUT carcinoma), NUTM1 translocation has also been reported in mesenchymal tumors, but is exceedingly rare. Here, we describe a series of 8 NUTM1 -rearranged sarcomas to further characterize the clinicopathologic features of this emerging entity. This cohort included 2 males and 6 females with age ranging from 24 to 64 years (mean: 51 y; median: 56 y). Tumors occurred in the colon (2), abdomen (2), jejunum (1), esophagus (1), lung (1) and infraorbital region (1). At diagnosis, 6 patients presented with metastatic disease. Tumor size ranged from 1 to 10.5 cm (mean: 6 cm; median: 5.5 cm). Histologically, 4 tumors were composed of primitive small round cells to epithelioid cells intermixed with variable spindle cells, while 3 tumors consisted exclusively of small round cells to epithelioid cells and 1 tumor consisted predominantly of high-grade spindle cells. The neoplastic cells were arranged in solid sheets, nests, or intersecting fascicles. Mitotic activity ranged from 1 to 15/10 HPF (median: 5/10 HPF). Other features included rhabdoid phenotype (4/8), pronounced nuclear convolutions (2/8), prominent stromal hyalinization (2/8), focally myxoid stroma (1/8), foci of osteoclasts (1/8), and necrosis (1/8). By immunohistochemistry, all tumors showed diffuse and strong nuclear staining of NUT protein, with variable expression of pancytokeratin (AE1/AE3) (2/8), CK18 (1/8), CD99 (3/8), NKX2.2 (2/8), cyclin D1 (2/8), desmin (2/8), BCOR (2/8), S100 (1/8), TLE1 (1/8), and synaptophysin (1/8). Seven of 8 tumors demonstrated NUTM1 rearrangement by fluorescence in situ hybridization analysis. RNA-sequencing analysis identified MXD4::NUTM1 (3/7), MXI1::NUTM1 (3/7), and MGA::NUTM1 (1/7) fusions, respectively. DNA-based methylation profiling performed in 2 cases revealed distinct methylation cluster differing from those of NUT carcinoma and undifferentiated small round cell and spindle cell sarcomas. At follow-up (range: 4 to 24 mo), 1 patient experienced recurrence at 8.5 months, 4 patients were alive with metastatic disease (5, 10, 11, and 24 mo after diagnosis), 3 patients remained well with no signs of recurrence or metastasis (4, 6, and 12 mo after diagnosis). Our study further demonstrated that NUTM1 -rearranged sarcoma had a broad range of clinicopathologic spectrum. NUT immunohistochemistry should be included in the diagnostic approach of monotonous undifferentiated small round, epithelioid to high-grade spindle cell malignancies that difficult to classify by conventional means. DNA-based methylation profiling might provide a promising tool in the epigenetic classification of undifferentiated sarcomas.

Interaction of the Transcription Factors BES1/BZR1 in Plant Growth and Stress Response.

Bri1-EMS Suppressor 1 (BES1) and Brassinazole Resistant 1 (BZR1) are two key transcription factors in the brassinosteroid (BR) signaling pathway, serving as crucial integrators that connect various signaling pathways in plants. Extensive genetic and biochemical studies have revealed that BES1 and BZR1, along with other protein factors, form a complex interaction network that governs plant growth, development, and stress tolerance. Among the interactome of BES1 and BZR1, several proteins involved in posttranslational modifications play a key role in modifying the stability, abundance, and transcriptional activity of BES1 and BZR1. This review specifically focuses on the functions and regulatory mechanisms of BES1 and BZR1 protein interactors that are not involved in the posttranslational modifications but are crucial in specific growth and development stages and stress responses. By highlighting the significance of the BZR1 and BES1 interactome, this review sheds light on how it optimizes plant growth, development, and stress responses.

Chronic HIV Infection Increases Monocyte NLRP3 Inflammasome-Dependent IL-1α and IL-1ß Release.

Antiretroviral treatment (ART) has converted HIV from a lethal disease to a chronic condition, yet co-morbidities persist. Incomplete immune recovery and chronic immune activation, especially in the gut mucosa, contribute to these complications. Inflammasomes, multi-protein complexes activated by innate immune receptors, appear to play a role in these inflammatory responses. In particular, preliminary data indicate the involvement of IFI16 and NLRP3 inflammasomes in chronic HIV infection. This study explores inflammasome function in monocytes from people with HIV (PWH); 22 ART-treated with suppressed viremia and 17 untreated PWH were compared to 33 HIV-negative donors. Monocytes were primed with LPS and inflammasomes activated with ATP in vitro. IFI16 and NLRP3 mRNA expression were examined in a subset of donors. IFI16 and NLRP3 expression in unstimulated monocytes correlated negatively with CD4 T cell counts in untreated PWH. For IFI16, there was also a positive correlation with viral load. Monocytes from untreated PWH exhibit increased release of IL-1α, IL-1ß, and TNF compared to treated PWH and HIV-negative donors. However, circulating monocytes in PWH are not pre-primed for inflammasome activation in vivo. The findings suggest a link between IFI16, NLRP3, and HIV progression, emphasizing their potential role in comorbidities such as cardiovascular disease. The study provides insights into inflammasome regulation in HIV pathogenesis and its implications for therapeutic interventions.

TRIM26 facilitates PRV infection through NDP52-mediated autophagic degradation of MAVS.

Pseudorabies virus (PRV) has evolved multiple strategies to evade host antiviral responses to benefit virus replication and establish persistent infection. Recently, tripartite motif 26 (TRIM26), a TRIM family protein, has been shown to be involved in a broad range of biological processes involved in innate immunity, especially in regulating viral infection. Herein, we found that the expression of TRIM26 was significantly induced after PRV infection. Surprisingly, the overexpression of TRIM26 promoted PRV production, while the depletion of this protein inhibited virus replication, suggesting that TRIM26 could positively regulate PRV infection. Further analysis revealed that TRIM26 negatively regulates the innate immune response by targeting the RIG-I-triggered type I interferon signalling pathway. TRIM26 was physically associated with MAVS independent of viral infection and reduced MAVS expression. Mechanistically, we found that NDP52 interacted with both TRIM26 and MAVS and that TRIM26-induced MAVS degradation was almost entirely blocked in NDP52-knockdown cells, demonstrating that TRIM26 degrades MAVS through NDP52-mediated selective autophagy. Our results reveal a novel mechanism by which PRV escapes host antiviral innate immunity and provide insights into the crosstalk among virus infection, autophagy, and the innate immune response.

Engineering mouse cell fate controller by rational design.

Cell fate is likely regulated by a common machinery, while components of this machine remain to be identified. Here we report the design and testing of engineered cell fate controller NanogBiD, fusing BiD or BRG1 interacting domain of SS18 with Nanog. NanogBiD promotes mouse somatic cell reprogramming efficiently in contrast to the ineffective native protein under multiple testing conditions. Mechanistic studies further reveal that it facilitates cell fate transition by recruiting the intended Brg/Brahma-associated factor (BAF) complex to modulate chromatin accessibility and reorganize cell state specific enhancers known to be occupied by canonical Nanog, resulting in precocious activation of multiple genes including Sall4, miR-302, Dppa5a and Sox15 towards pluripotency. Although we have yet to test our approach in other species, our findings suggest that engineered chromatin regulators may provide much needed tools to engineer cell fate in the cells as drugs era.

Inhibition of FBP1 expression by KMT5A through TWIST1 methylation is one of the mechanisms leading to chemoresistance in breast cancer.

Lysine methyltransferase 5A (KMT5A) is the sole mammalian enzyme known to catalyse the mono­methylation of histone H4 lysine 20 and non­histone proteins such as p53, which are involved in the occurrence and progression of numerous cancers. The present study aimed to determine the function of KMT5A in inducing docetaxel (DTX) resistance in patients with breast carcinoma by evaluating glucose metabolism and the underlying mechanism involved. The upregulation or downregulation of KMT5A­related proteins was examined after KMT5A knockdown in breast cancer (BRCA) cells by Tandem Mass Tag proteomics. Through differential protein expression and pathway enrichment analysis, the upregulated key gluconeogenic enzyme fructose­1,6­bisphosphatase 1 (FBP1) was discovered. Loss of FBP1 expression is closely related to the development and prognosis of cancers. A dual­luciferase reporter gene assay confirmed that KMT5A inhibited the expression of FBP1 and that overexpression of FBP1 could enhance the chemotherapeutic sensitivity to DTX through the suppression of KMT5A expression. The KMT5A inhibitor UNC0379 was used to verify that DTX resistance induced by KMT5A through the inhibition of FBP1 depended on the methylase activity of KMT5A. According to previous literature and interaction network structure, it was revealed that KMT5A acts on the transcription factor twist family BHLH transcription factor 1 (TWIST1). Then, it was verified that TWSIT1 promoted the expression of FBP1 by using a dual­luciferase reporter gene experiment. KMT5A induces chemotherapy resistance in BRCA cells by promoting cell proliferation and glycolysis. After the knockdown of the KMT5A gene, the FBP1 related to glucose metabolism in BRCA was upregulated. KMT5A knockdown expression and FBP1 overexpression synergistically inhibit cell proliferation and block cells in the G2/M phase. KMT5A inhibits the expression of FBP1 by methylating TWIST1 and weakening its promotion of FBP1 transcription. In conclusion, KMT5A was shown to affect chemotherapy resistance by regulating the cell cycle and positively regulate glycolysis­mediated chemotherapy resistance by inhibiting the transcription of FBP1 in collaboration with TWIST1. KMT5A may be a potential therapeutic target for chemotherapy resistance in BRCA.

BRG1 promotes liver cancer cell proliferation and metastasis by enhancing mitochondrial function and ATP5A1 synthesis through TOMM40.

Hepatocellular carcinoma (HCC) is one of the most lethal malignant tumors worldwide. Brahma-related gene 1 (BRG1), as a catalytic ATPase, is a major regulator of gene expression and is known to mutate and overexpress in HCC. The purpose of this study was to investigate the mechanism of action of BRG1 in HCC cells. In our study, BRG1 was silenced or overexpressed in human HCC cell lines. Transwell and wound healing assays were used to analyze cell invasiveness and migration. Mitochondrial membrane potential (MMP) and mitochondrial permeability transition pore (mPTP) detection were used to evaluate mitochondrial function in HCC cells. Colony formation and cell apoptosis assays were used to evaluate the effect of BRG1/TOMM40/ATP5A1 on HCC cell proliferation and apoptosis/death. Immunocytochemistry (ICC), immunofluorescence (IF) staining and western blot analysis were used to determine the effect of BRG1 on TOMM40, ATP5A1 pathway in HCC cells. As a result, knockdown of BRG1 significantly inhibited cell proliferation and invasion, promoted apoptosis in HCC cells, whereas BRG1 overexpression reversed the above effects. Overexpression of BRG1 can up-regulate MMP level, inhibit mPTP opening and activate TOMM40, ATP5A1 expression. Our results suggest that BRG1, as an oncogene, promotes HCC progression by regulating TOMM40 affecting mitochondrial function and ATP5A1 synthesis. Targeting BRG1 may represent a new and effective way to prevent HCC development.

PARP4 interacts with hnRNPM to regulate splicing during lung cancer progression.

BACKGROUND: The identification of cancer driver genes from sequencing data has been crucial in deepening our understanding of tumor biology and expanding targeted therapy options. However, apart from the most commonly altered genes, the mechanisms underlying the contribution of other mutations to cancer acquisition remain understudied. Leveraging on our whole-exome sequencing of the largest Asian lung adenocarcinoma (LUAD) cohort (n = 302), we now functionally assess the mechanistic role of a novel driver, PARP4. METHODS: In vitro and in vivo tumorigenicity assays were used to study the functional effects of PARP4 loss and mutation in multiple lung cancer cell lines. Interactomics analysis by quantitative mass spectrometry was conducted to identify PARP4's interaction partners. Transcriptomic data from cell lines and patient tumors were used to investigate splicing alterations. RESULTS: PARP4 depletion or mutation (I1039T) promotes the tumorigenicity of KRAS- or EGFR-driven lung cancer cells. Disruption of the vault complex, with which PARP4 is commonly associated, did not alter tumorigenicity, indicating that PARP4's tumor suppressive activity is mediated independently. The splicing regulator hnRNPM is a potentially novel PARP4 interaction partner, the loss of which likewise promotes tumor formation. hnRNPM loss results in splicing perturbations, with a propensity for dysregulated intronic splicing that was similarly observed in PARP4 knockdown cells and in LUAD cohort patients with PARP4 copy number loss. CONCLUSIONS: PARP4 is a novel modulator of lung adenocarcinoma, where its tumor suppressive activity is mediated not through the vault complex-unlike conventionally thought, but in association with its novel interaction partner hnRNPM, thus suggesting a role for splicing dysregulation in LUAD tumorigenesis.

Effect of the OPHN1 novel variant c.1025+1 G>A on RNA splicing: insights from a minigene assay.

This research analyzes the clinical data, whole-exome sequencing results, and in vitro minigene functional experiments of a child with developmental delay and intellectual disability. The male patient, aged 4, began experiencing epileptic seizures at 3 months post-birth and has shown developmental delay. Rehabilitation training was administered between the ages of one and two. There were no other significant family medical histories. Through comprehensive family exome genetic testing, a hemizygous variant in the 11th exon of the OPHN1 gene was identified in the affected child: c.1025 + 1G > A. Family segregation analysis confirmed the presence of this variant in the patient's mother, which had not been previously reported. According to the ACMG guidelines, this variant was classified as a likely pathogenic variant. In response to this variant, an in vitro minigene functional experiment was designed and conducted, confirming that the mutation affects the normal splicing of the gene's mRNA, resulting in a 56 bp retention on the left side of Intron 11. It was confirmed that OPHN1: c.1025 + 1G > A is the pathogenic cause of X-linked intellectual disabilities in the child, with clinical phenotypes including developmental delay and seizures.

A Ménage à trois: NLRC5, immunity, and metabolism.

The nucleotide-binding and oligomerization domain-like receptors (NLRs) NLR family CARD domain-containing protein 5 (NLRC5) and Class II Major Histocompatibility Complex Transactivator (CIITA) are transcriptional regulators of major histocompatibility complex (MHC) class I and class II genes, respectively. MHC molecules are central players in our immune system, allowing the detection of hazardous 'non-self' antigens and, thus, the recognition and elimination of infected or transformed cells from the organism. Recently, CIITA and NLRC5 have emerged as regulators of selected genes of the butyrophilin (BTN) family that interestingly are located in the extended MHC locus. BTNs are transmembrane proteins exhibiting structural similarities to B7 family co-modulatory molecules. The family member BTN2A2, which indeed contributes to the control of T cell activation, was found to be transcriptionally regulated by CIITA. NLRC5 emerged instead as an important regulator of the BTN3A1, BTN3A2, and BTN3A3 genes. Together with BTN2A1, BTN3As regulate non-conventional Vγ9Vδ2 T cell responses triggered by selected metabolites of microbial origin or accumulating in hematologic cancer cells. Even if endogenous metabolites conform to the canonical definition of 'self', metabolically abnormal cells can represent a danger for the organism and should be recognized and controlled by immune system cells. Collectively, new data on the role of NLRC5 in the expression of BTN3As link the mechanisms regulating canonical 'non-self' presentation and those marking cells with abnormal metabolic configurations for immune recognition, an evolutionary parallel that we discuss in this perspective review.