A four-year-old girl with pathogenic variant in the NAA10 gene and precocious puberty - case report and literature review.

The NAA10 gene encodes N-alpha-acetyltransferase 10 which plays an important role in cell growth, differentiation, DNA damage, metastasis, apoptosis, stress response and autophagy. Defects in the NAA10 gene correlate with the diagnosis of NAA10-related syndrome (Ogden syndrome). The most common symptoms of NAA10-related syndrome are: global developmental delay, non-verbal or limited speech, autism spectrum disorder, feeding difficulties, motor delay, muscle tone disturbances, and long QT syndrome. To-date, there are about 100 patients who have been reported with this condition. The case report presents the clinical study of a girl aged 4 years and 3 months diagnosed with Ogden syndrome. She had many characteristic features of the disorder, as well as precocious puberty. This girl represents the case of a patient with p.Arg83Cys mutation in NAA10 gene as well as precocious puberty.

NAA10 gene expression is associated with mesenchymal transition, dedifferentiation, and progression of clear cell renal cell carcinoma.

INTRODUCTION: We aimed to investigate the expression and prognostic role of NAA10 in clear cell renal cell carcinoma (ccRCC). MATERIAL AND METHODS: We performed a gene expression and survival analysis based on the human cancer genome atlas database of ccRCC patients (TCGA-KIRC). RESULTS: The patients in the TCGA-KIRC (n = 537) were divided into two subgroups: NAA10-low and NAA10-high expression groups. NAA10-high ccRCC exhibited higher T stages (p = 0.002), a higher frequency of distant metastasis (p = 0.018), more advanced AJCC stages (p < 0.001), a lower overall survival time (p = 0.036), and a lower survival rate (p < 0.001). NAA10-high ccRCC was associated with increased activity of non-specific oncogenic pathways, including oxidative phosphorylation (p < 0.001) and cell cycle progression [G2 to M phase transition (p = 0.045) and E2F targets (p < 0.001)]. Additionally, the NAA10-high tumors showed reduced apoptosis via TRIAL pathways (p < 0.001) and increased levels of activity that promoted epithelial-mesenchymal transition (p = 0.026) or undifferentiation (p = 0.01). In ccRCC, NAA10 expression was found to be a negative prognostic factor in both non-metastatic (p < 0.001) and metastatic tumors (p = 0.032). CONCLUSIONS: In ccRCC, NAA10 expression was shown to be a negative prognostic factor related to tumor progression rather than tumor initiation, and high NAA10 expression promoted epithelial-mesenchymal transition and undifferentiation.

Multiple impacts of Naa10p on cancer progression: Molecular functions and clinical prospects.

Nα-acetyltransferase 10 protein (Naa10p) is known as the catalytic subunit of N-terminal acetyltransferases A (NatA) complex, associating with Naa15p to acetylate N-termini of the human proteome. Recent investigations have unveiled additional functions for Naa10p, encompassing lysine ε-acetylation and acetyltransferase-independent activities. Its pleiotropic roles have been implicated in diverse physiological and pathological contexts. Emerging evidence has implicated Naa10p in cancer progression, demonstrating dual attributes as an oncogene or a tumor suppressor contingent on the cancer type and acetyltransferase activity context. In this comprehensive review, we present a pan-cancer analysis aimed at elucidating the intricacies underlying Naa10p dysregulation in cancer. Our findings propose the potential involvement of c-Myc as a modulatory factor influencing Naa10p expression. Moreover, we provide a consolidated summary of recent advancements in understanding the intricate molecular underpinnings through which Naa10p contributes to cancer cell proliferation and metastasis. Furthermore, we delve into the multifaceted nature of Naa10p's roles in regulating cancer behaviors, potentially attributed to its interactions with a repertoire of partner proteins. Through an exhaustive exploration of Naa10p's functions, spanning its acetylation activity and acetyltransferase-independent functionalities, this review offers novel insights with implications for targeted therapeutic strategies involving this pivotal protein in the realm of cancer therapeutics.

NAA10 overexpression dictates distinct epigenetic, genetic, and clinicopathological characteristics in adult gliomas.

NAA10 is a novel biomarker of cancer progression. The oncogenic and biological mechanisms of NAA10 in human malignancies are controversial and remain to be elucidated. Herein, we investigated the biological and clinicopathological implications of NAA10 gene expression in adult gliomas. We collected data from The Human Cancer Genome Atlas (TCGA) database, including patients from TCGA-GBM and TCGA-LGG projects. In total, there were 666 patients from the 2 projects (513 and 153 from TCGA-LGG and TCGA-GBM, respectively). Different analyses (pathway, DNA methylation, and survival analyses) require further specific case eliminations. Based on NAA10 expression, we divided 666 tumors into 2 subgroups: NAA10-high and NAA10-low glioma. There were higher activities of cell proliferation, metabolic reprogramming, DNA repair, angiogenesis, epithelial-mesenchymal transition, TNF-α, IL6/JAK/STAT6, mTORC1 signaling, and MYC targets in NAA10-high glioma, while P53, TGF-ß, Wnt, and Hedgehog pathways were highly expressed by NAA10-low gliomas. t-distributed stochastic neighbors embedding dimension reduction of DNA methylation also showed a high distribution of NAA10-high gliomas in distinct clusters. Survival analyses showed that high NAA10 expression was an independent prognostic factor. NAA10 expression dictated epigenetic, genetic, and clinicopathological differences in adult glioma. Further studies are required to investigate the detailed NAA10 oncogenic mechanisms and to validate NAA10 immunohistochemistry.

Naa10p promotes cell invasiveness of esophageal cancer by coordinating the c-Myc and PAI1 regulatory axis.

N-α-acetyltransferase 10 protein, Naa10p, is involved in various cellular functions impacting tumor progression. Due to its capacity to acetylate a large spectrum of proteins, both oncogenic and tumor-suppressive roles of Naa10p have been documented. Here, we report an oncogenic role of Naa10p in promoting metastasis of esophageal cancer. NAA10 is more highly expressed in esophageal cancer tissues compared to normal tissues. Higher NAA10 expression also correlates with poorer survival of esophageal cancer patients. We found that NAA10 expression was transcriptionally regulated by the critical oncogene c-Myc in esophageal cancer. Furthermore, activation of the c-Myc-Naa10p axis resulted in upregulated cell invasiveness of esophageal cancer. This increased cell invasiveness was also elucidated to depend on the enzymatic activity of Naa10p. Moreover, Naa10p cooperated with Naa15p to interact with the protease inhibitor, PAI1, and prevent its secretion. This inhibition of PAI1 secretion may derive from the N-terminal acetylation effect of the Naa10p/Naa15p complex. Our results establish the significance of Naa10p in driving metastasis in esophageal cancer by coordinating the c-Myc-PAI1 axis, with implications for its potential use as a prognostic biomarker and therapeutic target for esophageal cancer.

iTRAQ and two-dimensional-LC-MS/MS reveal NAA10 is a potential biomarker in esophageal squamous cell carcinoma.

PURPOSE: Esophageal squamous cell carcinoma (ESCC) is one of the most common and serious malignancies in China. However, the exact mechanisms of tumor progression are still unclear. Thus, identifying biomarkers for early diagnosis, prognostic and recurrence assessment of ESCC is necessary. EXPERIMENTAL DESIGN: iTRAQ was used to identify differentially expressed proteins (DEPs) in tumor tissues. N-alpha-acetyltransferase 10 (NAA10) is confirmed and validated by immunohistochemistry and western blotting. Furthermore, the effects of NAA10 on TE-1 cells were detected by CCK-8, colonies formation, anchorage-independent growth in soft agar, migration and transwell assays. LinkedOmics was used to identify differential gene expression with NAA10 and to analyze Gene Ontology and KEGG pathways. Coexpression gene network was conducted by the STRING database and Cytoscape software (MCODE plug-in). RESULTS: 516 DEPs were identified. NAA10 was downregulated in cancer tissues and selected for further confirmed. Furthermore, NAA10 can inhibit proliferation and tumorigenesis, and suppress migration and invasion of TE-1. Functional network analysis suggested that NAA10 regulates the ribosome pathways involving eight ribosomal proteins. CONCLUSION AND CLINICAL RELEVANCE: These findings clearly demonstrated that NAA10 is a tumor suppressor and novel potential biomarker for ESCC, laying a foundation for further study of the role of NAA10 in carcinogenesis.

Acetilación N-terminal, acetiltransferasas y mutaciones en subunidad auxiliar NAA15 de N-terminal acetiltransferasa A, asociadas a discapacidad intelectual y trastorno del espectro autista: una revisión bibliográfica / N-terminal acetylation, acetyltransferases and variants in NAA15 auxiliary subunit of the N-terminal acetyltransferase A associated with intellectual disability and autism spectrum disorder: a literature review

Las N-terminal acetiltransferasas (NaT) son fundamentales en el desarrollo, funcionamiento y vida media celular, acetilando gran parte del proteoma humano. Entre las ocho NaT identificadas, N-terminal acetiltransferasa A (NaTA) acetila a un mayor número de sustratos, teniendo además un rol fundamental en el neurodesarrollo. Previamente, estudios han demostrado que mutaciones en la subunidad catalítica de NaTA, NAA10, se asocian con trastornos del neurodesarrollo. Sin embargo, nuevas líneas investigativas sugieren que mutaciones de la subunidad auxiliar, NAA15, también tendrían un rol importante en el desarrollo de estos trastornos. Esta revisión se realiza con el objetivo de recopilar evidencia sobre variantes de NAA15 relacionadas con Discapacidad Intelectual (DI) y Trastorno de Espectro Autista (TEA). Se consultaron fuentes actualizadas sobre acetilación N-terminal, NaT, DI y TEA y mutaciones reportadas de NAA15 y sus expresiones fenotípicas, publicadas entre 2011 y 2022. Se concluye que, aun cuando existe relación entre mutaciones de NAA15, DI y TEA, todavía es necesario esclarecer los mecanismos fisiopatológicos de estos trastornos, el rol de NaTA y el impacto de variantes de sus subunidades en las vías moleculares y el fenotipo, lo que se dificulta por razones que van desde la complejidad de estas vías hasta el elevado costo de análisis genéticos. Se sugiere continuar la investigación en esta área, para comprender las bases moleculares subyacentes a estos trastornos y el rol de las mutaciones en subunidades de NaTA, con el fin último de estudiar potenciales tratamientos que mejoren la calidad de vida de las personas con estos trastornos y sus familias.

Nt-acetyltransferases (NaT) are essential in cell development, function and half-life, catalyzing most of the human proteome. Among the eight NaTs identified, N-terminal acetyltransferase A (NaTA) acetylates a greater number of substrates, also having a fundamental role in neurodevelopment. Previously, studies have shown that mutations in the catalytic subunit of NaTA, NAA10, are associated with neurodevelopmental disorders. However, new research lines suggest that mutations of the NAA15 helper subunit also plays an important role in the development of these disorders. This review is carried out with the objective of gathering evidence on NAA15 variants related to Intellectual Disability (ID) and Autism Spectrum Disorder (ASD). Updated sources on N-terminal acetylation, N-acetyltransferases, DI and TEA and reported mutations of NAA15 and their phenotypic expressions, published between 2011 and 2022 were consulted. It is concluded that even though there is a relationship between mutations of NAA15, ID and ASD exists, it is still necessary to clarify the pathophysiological mechanisms of these disorders, the role of NaTA and the impact of variants of its subunits in the molecular pathways and in the phenotype, for reasons ranging from the complexity of these pathways to the high cost of genetic testing. It is suggested to continue research in this area, to understand the molecular bases underlying these disorders and the role of mutations in NatA subunits, with the ultimate aim of studying potential treatments that improve the quality of life of people with these disorders and their families.

Naa10p and IKKα interaction regulates EMT in oral squamous cell carcinoma via TGF-ß1/Smad pathway.

Epithelial-mesenchymal transition (EMT) has been contributed to increase migration and invasion of cancer cells. However, the correlate of Naa10p and IKKα with EMT in oral squamous cell carcinoma (OSCC) is not yet fully understood. In our present study, we found N-α-acetyltransferase 10 protein (Naa10p) and IκB kinase α (IKKα) were abnormally abundant in oral squamous cell carcinoma (OSCC). Bioinformatic results indicate that the expression of Naa10p and IKKα is correlated with TGF-ß1/Smad and EMT-related molecules. The Transwell migration, invasion, qRT-PCR and Western blot assay indicated that Naa10p repressed OSCC cell migration, invasion and EMT, whereas IKKα promoted TGF-ß1-mediated OSCC cell migration, invasion and EMT. Mechanistically, Naa10p inhibited IKKα activation of Smad3 through the interaction with IKKα directly in OSCC cells after TGF-ß1 stimulation. Notably, knockdown of Naa10p reversed the IKKα-induced change in the migration, invasion and EMT-related molecules in OSCC cells after TGF-ß1 stimulation. These findings suggest that Naa10p interacted with IKKα mediates EMT in OSCC cells through TGF-ß1/Smad, a novel pathway for preventing OSCC.

Identification of novel prognostic biomarkers by integrating multi-omics data in gastric cancer.

BACKGROUND: Gastric cancer is a fatal gastrointestinal cancer with high morbidity and poor prognosis. The dismal 5-year survival rate warrants reliable biomarkers to assess and improve the prognosis of gastric cancer. Distinguishing driver mutations that are required for the cancer phenotype from passenger mutations poses a formidable challenge for cancer genomics. METHODS: We integrated the multi-omics data of 293 primary gastric cancer patients from The Cancer Genome Atlas (TCGA) to identify key driver genes by establishing a prognostic model of the patients. Analyzing both copy number alteration and somatic mutation data helped us to comprehensively reveal molecular markers of genomic variation. Integrating the transcription level of genes provided a unique perspective for us to discover dysregulated factors in transcriptional regulation. RESULTS: We comprehensively identified 31 molecular markers of genomic variation. For instance, the copy number alteration of WASHC5 (also known as KIAA0196) frequently occurred in gastric cancer patients, which cannot be discovered using traditional methods based on significant mutations. Furthermore, we revealed that several dysregulation factors played a hub regulatory role in the process of biological metabolism based on dysregulation networks. Cancer hallmark and functional enrichment analysis showed that these key driver (KD) genes played a vital role in regulating programmed cell death. The drug response patterns and transcriptional signatures of KD genes reflected their clinical application value. CONCLUSIONS: These findings indicated that KD genes could serve as novel prognostic biomarkers for further research on the pathogenesis of gastric cancers. Our study elucidated a multidimensional and comprehensive genomic landscape and highlighted the molecular complexity of GC.

NAA10 p.(N101K) disrupts N-terminal acetyltransferase complex NatA and is associated with developmental delay and hemihypertrophy.

Nearly half of all human proteins are acetylated at their N-termini by the NatA N-terminal acetyltransferase complex. NAA10 is evolutionarily conserved as the catalytic subunit of NatA in complex with NAA15, but may also have NatA-independent functions. Several NAA10 variants are associated with genetic disorders. The phenotypic spectrum includes developmental delay, intellectual disability, and cardiac abnormalities. Here, we have identified the previously undescribed NAA10 c.303C>A and c.303C>G p.(N101K) variants in two unrelated girls. These girls have developmental delay, but they both also display hemihypertrophy a feature normally not observed or registered among these cases. Functional studies revealed that NAA10 p.(N101K) is completely impaired in its ability to bind NAA15 and to form an enzymatically active NatA complex. In contrast, the integrity of NAA10 p.(N101K) as a monomeric acetyltransferase is intact. Thus, this NAA10 variant may represent the best example of the impact of NatA mediated N-terminal acetylation, isolated from other potential NAA10-mediated cellular functions and may provide important insights into the phenotypes observed in individuals expressing pathogenic NAA10 variants.

NAA10 promotes proliferation of renal cell carcinoma by upregulating UPK1B.

OBJECTIVE: The purpose of this study was to illustrate the role of NAA10 in aggravating the malignant progression of renal cell carcinoma (RCC) by upregulating UPK1B. PATIENTS AND METHODS: NAA10 levels in RCC tissues and paracancerous tissues were detected. Thereafter, the potential relationship between NAA10 level and clinical parameters of RCC patients was analyzed. After knockdown of NAA10, changes in proliferative potential of 786-O and Caki-1 cells were examined by cell counting kit-8 (CCK-8), colony formation and 5-Ethynyl-2'-deoxyuridine (EdU) assay. Finally, the regulatory role of NAA10 in the downstream gene UPK1B and the involvement of UPK1B in the development of RCC were determined via rescue experiments. RESULTS: NAA10 was upregulated in RCC tissues than paracancerous tissues. Tumor staging was much worse in RCC patients expressing a higher level of NAA10. Knockdown of NAA10 inhibited proliferative potential and downregulated UPK1B in RCC cells. Besides, NAA10 level was identified to be positively linked to UPK1B level in RCC tissues. At last, overexpression of UPK1B was able to abolish the inhibitory effect of silenced NAA10 on RCC proliferation. CONCLUSIONS: NAA10 level is closely linked to tumor staging and poor prognosis in RCC patients. NAA10 aggravates the malignant progression of RCC by upregulating UPK1B and may be a specific biomarker in RCC.

Metagenomic characterization of lysine acetyltransferases in human cancer and their association with clinicopathologic features.

Lysine acetyltransferases (KATs) are a highly diverse group of epigenetic enzymes that play important roles in various cellular processes including transcription, signal transduction, and cellular metabolism. However, our knowledge of the genomic and transcriptomic alterations of KAT genes and their clinical significance in human cancer remains incomplete. We undertook a metagenomic analysis of 37 KATs in more than 10 000 cancer samples across 33 tumor types, focusing on breast cancer. We identified associations among recurrent genetic alteration, gene expression, clinicopathologic features, and patient survival. Loss-of-function analysis was carried out to examine which KAT has important roles in growth and viability of breast cancer cells. We identified that a subset of KAT genes, including NAA10, KAT6A, and CREBBP, have high frequencies of genomic amplification or mutation in a spectrum of human cancers. Importantly, we found that 3 KATs, NAA10, ACAT2, and BRD4, were highly expressed in the aggressive basal-like subtype, and their expression was significantly associated with disease-free survival. Furthermore, we showed that depletion of NAA10 inhibits basal-like breast cancer growth in vitro. Our findings provide a strong foundation for further mechanistic research and for developing therapies that target NAA10 or other KATs in human cancer.

Diverse roles of arrest defective 1 in cancer development.

Arrest defective 1 is an acetyltransferase that acetylates N-terminal amino acid or internal lysine residues of its target proteins. By acetylating its target proteins, ARD1 plays roles in many cellular activities, including proliferation, differentiation, autophagy, and apoptosis. In recent years, a number of investigations have emerged reporting the dysregulated expression of ARD1 in different types of cancer, including lung, liver, pancreas, breast, prostate, and colon cancer. Furthermore, the expression level of ARD1 in cancer tissues has been correlated with the progression and metastasis of the cancer and the survival of cancer patients. Consequently, mechanistic studies have revealed that ARD1-mediated protein acetylation plays an important role in modulating several cellular events that are important for cancer development, such as cell cycle progression, cell death, and migration. On the basis of this evidence, targeting of ARD1 has been proposed as a promising avenue for the development of novel cancer therapeutics. This review summarizes the biological functions of ARD1 in different types of cancer and provides a deep insight into the biochemical activities of ARD1 during tumor progression.

miR-342 suppresses the proliferation and invasion of acute myeloid leukemia by targeting Naa10p.

Accumulating studies showed that microRNAs are maintaining a variety of important biological processes but the underlying mechanism in proliferation and tumourigenicity is unclear. In this study we show that miR-342 expression in bone marrow and patients' sera of childhood acute myeloid leukemia (AML) was both significantly higher than those in the corresponding normal controls. Functional assays demonstrated that forced expression of miR-342 significantly suppresses AML cell proliferation and G1/S transition of leukemia cells. Mechanistically, bioinformatics prediction and luciferase reporter assay identified N-a-acetyltransferase 10 protein (Naa10p) as a direct molecular target of miR-342, Naa10p siRNA significantly repressed cell proliferation and increased cell apoptosis. In conclusion, our study confirmed that miR-342/Naa10p plays key roles in AML progression, providing insights into underlying mechanisms of AML pathogenesis and also a potential therapeutic target for this malignancy.

Naa10p Inhibits Beige Adipocyte-Mediated Thermogenesis through N-α-acetylation of Pgc1α.

Diet-induced obesity can be caused by impaired thermogenesis of beige adipocytes, the brown-like adipocytes in white adipose tissue (WAT). Promoting brown-like features in WAT has been an attractive therapeutic approach for obesity. However, the mechanism underlying beige adipocyte formation is largely unknown. N-α-acetyltransferase 10 protein (Naa10p) catalyzes N-α-acetylation of nascent proteins, and overexpression of human Naa10p is linked to cancer development. Here, we report that both conventional and adipose-specific Naa10p deletions in mice result in increased energy expenditure, thermogenesis, and beige adipocyte differentiation. Mechanistically, Naa10p acetylates the N terminus of Pgc1α, which prevents Pgc1α from interacting with Pparγ to activate key genes, such as Ucp1, involved in beige adipocyte function. Consistently, fat tissues of obese human individuals show higher NAA10 expression. Thus, Naa10p-mediated N-terminal acetylation of Pgc1α downregulates thermogenic gene expression, making inhibition of Naa10p enzymatic activity a potential strategy for treating obesity.

Inverse correlation between Naa10p and Pirh2 expression and the combined prognostic value in oral squamous cell carcinoma patients.

BACKGROUND: This study aims to explore the associations between N-α-acetyltransferase 10 protein (Naa10p) and p53-induced protein with a RING-H2 domain (Pirh2) expression and clinicopathological characteristics in oral squamous cell carcinoma (OSCC). METHODS: Immunohistochemistry was performed to detect Naa10p and Pirh2 levels containing 118 OSCC specimens, and additional analyses were used to determine correlations between Naa10p and Pirh2 expressions, generate survival curves, and perform univariate and multivariate statistical analyses. Further, quantitative real-time PCR (qRT-PCR) and western blot were employed to examine Naa10p and Pirh2 expression level in OSCC patients' samples. We further validated the result using RNAseq data from The Cancer Genome Atlas (TCGA) and mRNA array data from GSE31056 and GSE30784. RESULTS: Naa10p and Pirh2 are overexpression, and the protein level of Naa10p was negatively correlated with that of Pirh2 in OSCC tissues. Multivariate Cox proportional hazard regression analysis showed that positive Naa10p expression and negative Pirh2 expression were both independent good prognostic factors for OSCC patients. Furthermore, the Naa10p-positive/Pirh2-negative group has the best prognosis among all OSCC patients. Results from qRT-PCR showed the higher expression level of Naa10 and lower expression level of Pirh2 in tumor tissues than adjacent normal tissues. TCGA database and data from GSE31056 and GSE30784 showed the similar result. The correlation analysis showed that the mRNA level of Naa10 was negatively correlated that of Pirh2. CONCLUSION: The expression of Naa10p is negatively correlated with that of Pirh2, and positive Naa10p and negative Pirh2 might be independent biomarkers for better OSCC prognoses.

The N-end rule pathway enzyme Naa10 supports epiblast specification in mouse embryonic stem cells by modulating FGF/MAPK.

N-terminal acetylation (Nt-acetylation) refers to the acetylation of the free α-amino group at the N-terminus of a polypeptide. While the effects of Nt-acetylation are multifaceted, its most known function is in the acetylation-dependent N-end rule protein degradation pathway (Ac/N-end rule pathway), where Nt-acetylation is recognized as a degron by designated E3 ligases, eventually leading to target degradation by the ubiquitin-proteasome system. Naa10 is the catalytic subunit of the major Nt-acetylation enzyme NatA, which Nt-acetylates proteins whose second amino acid has a small side chain. In humans, NAA10 is the responsible mutated gene in Ogden syndrome and is thought to play important roles in development. However, it is unclear how the Ac/N-end rule pathway affects the differentiation ability of mouse embryonic stem cells (mESCs). We hypothesized that the balance of pluripotency factors may be maintained by the Ac/N-end rule pathway. Thus, we established Naa10 knockout mESCs to test this hypothesis. We found that Naa10 deficiency attenuated differentiation towards the epiblast lineage, deviating towards primitive endoderm. However, this was not caused by disturbing the balance of pluripotency factors, rather by augmenting FGF/MAPK signaling.

RNA interference screen identifies NAA10 as a regulator of PXR transcription.

The pregnane X receptor (PXR) is a principal xenobiotic receptor crucial in the detection, detoxification, and clearance of toxic substances from the body. PXR plays a vital role in the metabolism and disposition of drugs, and elevated PXR levels contribute to cancer drug resistance. Therefore, to modulate PXR activity and mitigate drug resistance, it is imperative to fully understand its regulation. To this end, we screened a transcription factor siRNA library in pancreatic cancer cells that express high levels of PXR. Through a comprehensive deconvolution process, we identified N-alpha-acetyltransferase 10 (NAA10) as a factor in the transcriptional machinery regulating PXR transcription. Because no one single factor has 100% operational control of PXR transcriptional regulation, our results together with other previous findings suggest that the transcriptional regulation of PXR is complex and that multiple factors contribute to the process including NAA10.

Naa15 knockdown enhances c2c12 myoblast fusion and induces defects in zebrafish myotome morphogenesis.

The understanding of muscle tissue formation and regeneration is essential for the development of therapeutic approaches to treat muscle diseases or loss of muscle mass and strength during ageing or cancer. One of the critical steps in muscle formation is the fusion of muscle cells to form or regenerate muscle fibres. To identify new genes controlling myoblast fusion, we performed a siRNA screen in c2c12 myoblasts. The genes identified during this screen were then studied in vivo by knockdown in zebrafish using morpholino. We found that N-alpha-acetyltransferase 15 (Naa15) knockdown enhanced c2c12 myoblast fusion, suggesting that Naa15 negatively regulates myogenic cell fusion. We identified two Naa15 orthologous genes in the zebrafish genome: Naa15a and Naa15b. These two orthologs were expressed in the myogenic domain of the somite. Knockdown of zebrafish Naa15a and Naa15b genes induced a "U"-shaped segmentation of the myotome and alteration of myotome boundaries, resulting in the formation of abnormally long myofibres spanning adjacent somites. Taken together, these results show that Naa15 regulates myotome formation and myogenesis in fish.