The majority of breast cancers are primarily hormone‐sensitive and can be managed by endocrine therapy, although therapy‐resistant or hormone‐refractory cancers need alternative treatments. Recently, ...increasing attention is being paid to RNA‐binding proteins (RBP) in cancer pathophysiology. The precise role of RBP in breast cancer, however, remains to be clarified. We herein show that an RBP non‐POU domain‐containing octamer binding (NONO) plays a critical role in the pathophysiology of breast cancers regardless of their hormone dependency. Clinicopathological and immunohistochemical study of 127 breast cancer cases showed that NONO is a significant independent prognostic factor for breast cancer patients. Notably, siRNA‐mediated NONO knockdown substantially repressed the proliferation of both hormone‐sensitive MCF‐7 and hormone‐refractory MB‐MDA‐231 breast cancer cells. Integrative analysis combined with expression microarray and RIP‐sequencing (RNA immunoprecipitation‐sequencing) showed that NONO post‐transcriptionally regulates the expression of cell proliferation‐related genes by binding to their mRNAs, as exemplified by S‐phase‐associated kinase 2 and E2F transcription factor 8. Overall, these results suggest that NONO is a key regulator for breast cancer proliferation through the pre‐mRNA splicing of cell proliferation‐related genes and could be a potential new diagnostic and therapeutic target for advanced disease.
The present study shows that Drosophila behavior human splicing family RNA‐binding protein NONO plays a critical role in breast cancer tumorigenesis. Clinicopathological study defines that NONO immunoreactivity significantly correlates with poor overall and distant disease‐free survival of breast cancer patients. Cell‐based experiments show that NONO contributes to breast cancer proliferation by regulating SKP2 and E2F8 expression at the post‐transcriptional level. Our findings provide a new cancer strategy by applying NONO as a potential diagnostic and therapeutic target for breast cancer.
Non-pial neocortical astrocytes have historically been thought to comprise largely a nondiverse population of protoplasmic astrocytes. Here we show that astrocytes of the mouse somatosensory cortex ...manifest layer-specific morphological and molecular differences. Two- and three-dimensional observations revealed that astrocytes in the different layers possess distinct morphologies as reflected by differences in cell orientation, territorial volume, and arborization. The extent of ensheathment of synaptic clefts by astrocytes in layer II/III was greater than that by those in layer VI. Moreover, differences in gene expression were observed between upper-layer and deep-layer astrocytes. Importantly, layer-specific differences in astrocyte properties were abrogated in reeler and Dab1 conditional knockout mice, in which neuronal layers are disturbed, suggesting that neuronal layers are a prerequisite for the observed morphological and molecular differences of neocortical astrocytes. This study thus demonstrates the existence of layer-specific interactions between neurons and astrocytes, which may underlie their layer-specific functions.
Here, we review single-cell sequencing techniques for individual and multiomics profiling in single cells. We mainly describe single-cell genomic, epigenomic, and transcriptomic methods, and examples ...of their applications. For the integration of multilayered data sets, such as the transcriptome data derived from single-cell RNA sequencing and chromatin accessibility data derived from single-cell ATAC-seq, there are several computational integration methods. We also describe single-cell experimental methods for the simultaneous measurement of two or more omics layers. We can achieve a detailed understanding of the basic molecular profiles and those associated with disease in each cell by utilizing a large number of single-cell sequencing techniques and the accumulated data sets.
In mice, transcription initiates at the mid-one-cell stage and transcriptional activity dramatically increases during the two-cell stage, a process called zygotic gene activation (ZGA). Associated ...with ZGA is a marked change in the pattern of gene expression that occurs after the second round of DNA replication. To distinguish ZGA before and after the second-round DNA replication, the former and latter are called minor and major ZGA, respectively. Although major ZGA are required for development beyond the two-cell stage, the function of minor ZGA is not well understood. Transiently inhibiting minor ZGA with 5, 6-dichloro-1-β-D-ribofuranosyl-benzimidazole (DRB) resulted in the majority of embryos arresting at the two-cell stage and retention of the H3K4me3 mark that normally decreases. After release from DRB, at which time major ZGA normally occurred, transcription initiated with characteristics of minor ZGA but not major ZGA, although degradation of maternal mRNA normally occurred. Thus, ZGA occurs sequentially starting with minor ZGA that is critical for the maternal-to-zygotic transition.
Despite the recent discovery of tissue regeneration enhancers in highly regenerative animals, upstream and downstream genetic programs connected by these enhancers still remain unclear. Here, we ...performed a genome-wide analysis of enhancers and associated genes in regenerating nephric tubules of
Xenopus laevis
. Putative enhancers were identified using assay for transposase-accessible chromatin with high-throughput sequencing (ATAC-seq) and H3K27ac chromatin immunoprecipitation sequencing (ChIP-seq) analyses. Their target genes were predicted based on their proximity to enhancers on genomic DNA and consistency of their transcriptome profiles to ATAC-seq/ChIP-seq profiles of the enhancers. Motif enrichment analysis identified the central role of Krüppel-like factors (Klf) in the enhancer. Klf15, a member of the Klf family, directly binds enhancers and stimulates expression of regenerative genes, including
adrenoreceptor alpha 1A
(
adra1a
), whereas inhibition of Klf15 activity results in failure of nephric tubule regeneration. Moreover, pharmacological inhibition of Adra1a-signaling suppresses nephric tubule regeneration, while its activation promotes nephric tubule regeneration and restores organ size. These results indicate that Klf15-dependent adrenergic receptor signaling through regeneration enhancers plays a central role in the genetic network for kidney regeneration.
Plants monitor the ambient light conditions using several informational photoreceptors, including red/far-red light absorbing phytochrome. Phytochrome is widely believed to regulate the transcription ...of light-responsive genes by modulating the activity of several transcription factors. Here we provide evidence that phytochrome significantly changes alternative splicing (AS) profiles at the genomic level in Arabidopsis , to approximately the same degree as it affects steady-state transcript levels. mRNA sequencing analysis revealed that 1,505 and 1,678 genes underwent changes in their AS and steady-state transcript level profiles, respectively, within 1 h of red light exposure in a phytochrome-dependent manner. Furthermore, we show that splicing factor genes were the main early targets of AS control by phytochrome, whereas transcription factor genes were the primary direct targets of phytochrome-mediated transcriptional regulation. We experimentally validated phytochrome-induced changes in the AS of genes that are involved in RNA splicing, phytochrome signaling, the circadian clock, and photosynthesis. Moreover, we show that phytochrome-induced AS changes of SPA1-RELATED 3 , the negative regulator of light signaling, physiologically contributed to promoting photomorphogenesis. Finally, photophysiological experiments demonstrated that phytochrome transduces the signal from its photosensory domain to induce light-dependent AS alterations in the nucleus. Taking these data together, we show that phytochrome directly induces AS cascades in parallel with transcriptional cascades to mediate light responses in Arabidopsis .
Significance Plants adapt to their fluctuating environment by monitoring surrounding light conditions through several photoreceptors, such as phytochrome. It is widely believed that upon absorbing red light, phytochrome induces plant light responses by regulating the transcription of numerous target genes. In this study, we provide clear evidence that phytochrome controls not only transcription, but also alternative splicing in Arabidopsis . We reveal that 6.9% of the annotated genes in the Arabidopsis genome undergo rapid changes in their alternative splicing patterns in a red light- and phytochrome-dependent manner. Our results demonstrate that phytochrome simultaneously regulates two different aspects of gene expression, namely transcription and alternative splicing to mediate light responses in plants.
Long-read sequencing of full-length cDNAs enables the detection of structures of aberrant splicing isoforms in cancer cells. These isoforms are occasionally translated, presented by HLA molecules, ...and recognized as neoantigens. This study used a long-read sequencer (MinION) to construct a comprehensive catalog of aberrant splicing isoforms in non-small-cell lung cancers, by which novel isoforms and potential neoantigens are identified.
Full-length cDNA sequencing is performed using 22 cell lines, and a total of 2021 novel splicing isoforms are identified. The protein expression of some of these isoforms is then validated by proteome analysis. Ablations of a nonsense-mediated mRNA decay (NMD) factor, UPF1, and a splicing factor, SF3B1, are found to increase the proportion of aberrant transcripts. NetMHC evaluation of the binding affinities to each type of HLA molecule reveals that some of the isoforms potentially generate neoantigen candidates. We also identify aberrant splicing isoforms in seven non-small-cell lung cancer specimens. An enzyme-linked immune absorbent spot assay indicates that approximately half the peptide candidates have the potential to activate T cell responses through their interaction with HLA molecules. Finally, we estimate the number of isoforms in The Cancer Genome Atlas (TCGA) datasets by referring to the constructed catalog and found that disruption of NMD factors is significantly correlated with the number of splicing isoforms found in the TCGA-Lung Adenocarcinoma data collection.
Our results indicate that long-read sequencing of full-length cDNAs is essential for the precise identification of aberrant transcript structures in cancer cells.
Developing therapeutic approaches are necessary for treating hormone-refractory prostate cancer. Activation of androgen receptor (AR) and its variants’ expression along with the downstream signals ...are mostly important for disease progression. However, the mechanism for marked increases of AR signals and its expression is still unclear. Here, we revealed that various spliceosome genes are aberrantly induced by RNA-binding protein PSF, leading to enhancement of the splicing activities for AR expression. Our high-speed sequence analyses identified global PSF-binding transcripts. PSF was shown to stabilize and activate key long noncoding RNAs and AR-regulated gene expressions in prostate cancer cells. Interestingly, mRNAs of spliceosome-related genes are putative primary targets of PSF. Their gene expressions are up-regulated by PSF in hormone-refractory prostate cancer. Moreover, PSF coordinated these spliceosome proteins to form a complex to promote AR splicing and expression. Thus, targeting PSF and its related pathways implicates the therapeutic possibility for hormone-refractory prostate cancer.
The immune landscape varies among individuals. It determines the immune response and results in surprisingly diverse symptoms, even in response to similar external stimuli. However, the detailed ...mechanisms underlying such diverse immune responses have remained mostly elusive. The utilization of recently developed single‐cell multimodal analysis platforms has started to answer this question. Emerging studies have elucidated several molecular networks that may explain diversity with respect to age or other factors. An elaborate interplay between inherent physical conditions and environmental conditions has been demonstrated. Furthermore, the importance of modifications by the epigenome resulting in transcriptome variation among individuals is gradually being revealed. Accordingly, epigenomes and transcriptomes are direct indicators of the medical history and dynamic interactions with environmental factors. Coronavirus disease 2019 (COVID‐19) has recently become one of the most remarkable examples of the necessity of in‐depth analyses of diverse responses with respect to various factors to improve treatment in severe cases and to prevent viral transmission from asymptomatic carriers. In fact, determining why some patients develop serious symptoms is still a pressing issue. Here, we review the current “state of the art” in single‐cell analytical technologies and their broad applications to healthy individuals and representative diseases, including COVID‐19.
The immune landscape varies among individuals and leads to diverse immune responses even to similar external stimuli. Researchers have started to use single‐cell multimodal analytical technologies to reveal these differences. Here, we review the current “state of the art” in single‐cell analytical technologies and their broad applications to healthy individuals and representative diseases, including COVID‐19.
Alternative promoter usage is a proteome-expanding mechanism that allows multiple pre-mRNAs to be transcribed from a single gene. The impact of this mechanism on the proteome and whether it is ...positively exploited in normal organismal responses remain unclear. We found that the plant photoreceptor phytochrome induces genome-wide changes in alternative promoter selection in Arabidopsis thaliana. Through this mechanism, protein isoforms with different N termini are produced that display light-dependent differences in localization. For instance, shade-grown plants accumulate a cytoplasmic isoform of glycerate kinase (GLYK), an essential photorespiration enzyme that was previously thought to localize exclusively to the chloroplast. Cytoplasmic GLYK constitutes a photorespiratory bypass that alleviates fluctuating light-induced photoinhibition. Therefore, phytochrome controls alternative promoter selection to modulate protein localization in response to changing light conditions. This study suggests that alternative promoter usage represents another ubiquitous layer of gene expression regulation in eukaryotes that contributes to diversification of the proteome.
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•Phytochrome induces genome-wide changes in alternative promoter selection•Phytochrome-mediated alternative promoter selection modulates protein localization•This mechanism produces a cytoplasmic isoform of glycerate kinase (cytGLYK)•cytGLYK accumulates in shade to alleviate fluctuating light-induced photoinhibition
Light signaling through phytochrome receptors changes protein localization through alternative promoter selection, allowing plants to metabolically respond to changing light conditions.
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