Publications by authors named "Xiao-cui Yang"

Radix Fici Simplicissimae (RFS) is widely studied, and is in demand for its value in medicines and food products, with increased scientific focus on its cultivation and breeding. We used ultra-high-performance liquid chromatography quadrupole-orbitrap mass spectrometry-based metabolomics to elucidate the similarities and differences in phytochemical compositions of wild Radix Fici Simplicissimae (WRFS) and cultivated Radix Fici Simplicissimae (CRFS). Untargeted metabolomic analysis was performed with multivariate statistical analysis and heat maps to identify the differences.

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Objective: We aimed to explore the geographic differences in psychological symptoms, sleep quality, and quality of life (QoL) among adult patients with inflammatory bowel disease (IBD).

Methods: A unified questionnaire was developed to collect data on psychological status and QoL of IBD patients from 42 hospitals across 22 provinces, municipalities, and autonomous regions in China's mainland from September 2021 to May 2022.

Results: A total of 2478 patients with IBD were surveyed.

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Article Synopsis
  • U7 snRNP is a crucial endonuclease involved in processing histone pre-mRNAs in metazoans and has a unique composition compared to other spliceosomal snRNPs, lacking certain subunits and incorporating Lsm10 and Lsm11.
  • Recent research reveals that Lsm10 and Lsm11 interact with the methylosome complex, which includes PRMT5, involved in methylating proteins during assembly processes.
  • PRMT5 not only methylates specific arginine residues in Lsm11 but also modifies an arginine in SmE, suggesting that the unique methylation patterns of these proteins may be significant for the U7 snRNP assembly process.
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Introduction: Positive correlation between examination time and neoplasm detection using esophagogastroduodenoscopy (EGD) has been described by observational studies, but the effect of setting minimal examination time still requires investigation.

Methods: This prospective, 2-stage, interventional study was conducted in 7 tertiary hospitals in China, enrolling consecutive patients undergoing intravenously sedated diagnostic EGDs. In stage I, the baseline examination time was collected without informing the endoscopists.

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U7 snRNP is a multi-subunit endonuclease required for 3' end processing of metazoan replication-dependent histone pre-mRNAs. In contrast to the spliceosomal snRNPs, U7 snRNP lacks the Sm subunits D1 and D2 and instead contains two related proteins, Lsm10 and Lsm11. The remaining five subunits of the U7 heptameric Sm ring, SmE, F, G, B and D3, are shared with the spliceosomal snRNPs.

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In animal cells, replication-dependent histone pre-mRNAs are processed at the 3'-end by an endonucleolytic cleavage carried out by the U7 snRNP, a machinery that contains the U7 snRNA and many protein subunits. Studies on the composition of this machinery and understanding of its role in 3'-end processing were greatly facilitated by the development of an in vitro system utilizing nuclear extracts from mammalian cells 35 years ago and later from Drosophila cells. Most recently, recombinant expression and purification of the components of the machinery have enabled the full reconstitution of an active machinery and its complex with a model pre-mRNA substrate, using 13 proteins and 2 RNAs, and the determination of the structure of this active machinery.

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The histone locus body (HLB) is an evolutionarily conserved nuclear body that regulates the transcription and processing of replication-dependent (RD) histone mRNAs, which are the only eukaryotic mRNAs lacking a poly-A tail. Many nuclear bodies contain distinct domains, but how internal organization is related to nuclear body function is not fully understood. Here, we demonstrate using structured illumination microscopy that HLBs have a "core-shell" organization in which the internal core contains transcriptionally active RD histone genes.

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FLICE-associated huge protein (FLASH), Yin Yang 1-Associated Protein-Related Protein (YARP) and Nuclear Protein, Ataxia-Telangiectasia Locus (NPAT) localize to discrete nuclear structures called histone locus bodies (HLBs) where they control various steps in histone gene expression. Near the C-terminus, FLASH and YARP contain a highly homologous domain that interacts with the C-terminal region of NPAT. Structural aspects of the FLASH-NPAT and YARP-NPAT complexes and their role in histone gene expression remain largely unknown.

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Metazoan replication-dependent histone pre-mRNAs are cleaved at the 3' end by U7 snRNP, an RNA-guided endonuclease that contains U7 snRNA, seven proteins of the Sm ring, FLASH, and four polyadenylation factors: symplekin, CPSF73, CPSF100, and CstF64. A fully recombinant U7 snRNP was recently reconstituted from all 13 components for functional and structural studies and shown to accurately cleave histone pre-mRNAs. Here, we analyzed the activity of recombinant U7 snRNP in more detail.

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Article Synopsis
  • The processing of histone precursor mRNAs in metazoans involves the U7 small nuclear ribonucleoprotein and shares components with the typical cleavage and polyadenylation machinery.
  • Researchers recreated an active processing system using 13 proteins and two RNAs, revealing a unique structure that looks like an amphora with a long handle through cryo-electron microscopy.
  • The study shows that the endonuclease is ready for action when it recognizes the pre-mRNA bound to U7 snRNA, highlighting important steps in 3'-end processing for both canonical and snRNA pathways.
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In animal cells, replication-dependent histone pre-mRNAs are cleaved at the 3' end by U7 snRNP consisting of two core components: a ∼60-nucleotide U7 snRNA and a ring of seven proteins, with Lsm10 and Lsm11 replacing the spliceosomal SmD1 and SmD2. Lsm11 interacts with FLASH and together they recruit the endonuclease CPSF73 and other polyadenylation factors, forming catalytically active holo U7 snRNP. Here, we assembled core U7 snRNP bound to FLASH from recombinant components and analyzed its appearance by electron microscopy and ability to support histone pre-mRNA processing in the presence of polyadenylation factors from nuclear extracts.

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For many years, the exceptionally strong and rapidly formed interaction between biotin and streptavidin has been successfully utilized for partial purification of biologically important RNA/protein complexes. However, this strategy suffers from one major disadvantage that limits its broader utilization: the biotin/streptavidin interaction can be broken only under denaturing conditions that also disrupt the integrity of the eluted complexes, hence precluding their subsequent functional analysis and/or further purification by other methods. In addition, the eluted samples are frequently contaminated with the background proteins that nonspecifically associate with streptavidin beads, complicating the analysis of the purified complexes by silver staining and mass spectrometry.

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3' end cleavage of metazoan replication-dependent histone pre-mRNAs requires the multi-subunit holo-U7 snRNP and the stem-loop binding protein (SLBP). The exact composition of the U7 snRNP and details of SLBP function in processing remain unclear. To identify components of the U7 snRNP in an unbiased manner, we developed a novel approach for purifying processing complexes from Drosophila and mouse nuclear extracts.

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Cleavage of histone pre-mRNAs at the 3' end requires stem-loop binding protein (SLBP) and U7 snRNP that consists of U7 snRNA and a unique Sm ring containing two U7-specific proteins: Lsm10 and Lsm11. Lsm11 interacts with FLASH and together they bring a subset of polyadenylation factors to U7 snRNP, including the CPSF73 endonuclease that cleaves histone pre-mRNA. SLBP binds to a conserved stem-loop structure upstream of the cleavage site and acts by promoting an interaction between the U7 snRNP and a sequence element located downstream from the cleavage site.

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Objective To observe the effect of Naoxintong Capsule (NC) on carotid artery vas- cular remodeling (VR) in type 2 diabetes mellitus (T2DM) patients with subclinical vascular disease. Methods A total of 180 T2DM patients with subclinical atherosclerosis (AS) were randomly assigned to the observation group and the control group in the ratio of 1:1 , 90 in each group. All patients took conven- tional hypoglycemic therapy, and the choices of therapeutic drugs and doses were selected according to patients' conditions.

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Histone pre-mRNAs are cleaved at the 3' end by a complex that contains U7 snRNP, the FLICE-associated huge protein (FLASH) and histone pre-mRNA cleavage complex (HCC) consisting of several polyadenylation factors. Within the complex, the N terminus of FLASH interacts with the N terminus of the U7 snRNP protein Lsm11, and together they recruit the HCC. FLASH through its distant C terminus independently interacts with the C-terminal SANT/Myb-like domain of nuclear protein, ataxia-telangiectasia locus (NPAT), a transcriptional co-activator required for expression of histone genes in S phase.

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Nuclear protein, ataxia-telangiectasia locus (NPAT) and FLICE-associated huge protein (FLASH) are two major components of discrete nuclear structures called histone locus bodies (HLBs). NPAT is a key co-activator of histone gene transcription, whereas FLASH through its N-terminal region functions in 3' end processing of histone primary transcripts. The C-terminal region of FLASH contains a highly conserved domain that is also present at the end of Yin Yang 1-associated protein-related protein (YARP) and its Drosophila homologue, Mute, previously shown to localize to HLBs in Drosophila cells.

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3'-End cleavage of animal replication-dependent histone pre-mRNAs is controlled by the U7 snRNP. Lsm11, the largest component of the U7-specific Sm ring, interacts with FLASH, and in mammalian nuclear extracts these two proteins form a platform that recruits the CPSF73 endonuclease and other polyadenylation factors to the U7 snRNP. FLASH is limiting, and the majority of the U7 snRNP in mammalian extracts exists as a core particle consisting of the U7 snRNA and the Sm ring.

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Animal replication-dependent histone pre-mRNAs are processed at the 3' end by endonucleolytic cleavage that is not followed by polyadenylation. The cleavage reaction is catalyzed by CPSF73 and depends on the U7 snRNP and its integral component, Lsm11. A critical role is also played by the 220-kDa protein FLASH, which interacts with Lsm11.

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Nuclear bodies are protein- and RNA-containing structures that participate in a wide range of processes critical to genome function. Molecular self-organization is thought to drive nuclear body formation, but whether this occurs stochastically or via an ordered, hierarchical process is not fully understood. We addressed this question using RNAi and proteomic approaches in Drosophila melanogaster to identify and characterize novel components of the histone locus body (HLB), a nuclear body involved in the expression of replication-dependent histone genes.

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3'-end cleavage of histone pre-mRNAs is catalyzed by CPSF-73 and requires the interaction of two U7 snRNP-associated proteins, FLASH and Lsm11. Here, by using scanning mutagenesis we identify critical residues in human FLASH and Lsm11 that are involved in the interaction between these two proteins. We also demonstrate that mutations in the region of FLASH located between amino acids 50 and 99 do not affect binding of Lsm11.

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3' end processing of histone pre-mRNA requires U7 snRNP, which binds downstream of the cleavage site and recruits the endonuclease CPSF-73. U7 snRNP contains a unique Sm ring in which the canonical SmD2 protein is replaced by Lsm11. We used the yeast two-hybrid system to identify binding partners of Lsm11 and selected the proapoptotic protein FLASH.

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Cleavage of histone pre-mRNAs at the 3' end is guided by the U7 snRNP, which is a component of a larger 3'-end processing complex. To identify other components of this complex, we isolated proteins that stably associate with a fragment of histone pre-mRNA containing all necessary processing elements and a biotin affinity tag at the 5' end. Among the isolated proteins, we identified three well-characterized processing factors: the stem-loop binding protein (SLBP), which interacts with the stem-loop structure upstream of the cleavage site, and both Lsm11 and SmB, which are components of the U7-specific Sm ring.

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Human embryonic stem (hES) cells have an abbreviated G(1) phase of the cell cycle. How cells expedite G(1) events that are required for the initiation of S phase has not been resolved. One key regulatory pathway that controls G(1)/S-phase transition is the cyclin E/CDK2-dependent activation of the coactivator protein nuclear protein, ataxia-telangiectasia locus/histone nuclear factor-P (p220(NPAT)/HiNF-P) complex that induces histone gene transcription.

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Processing of histone pre-mRNA requires a single 3' endonucleolytic cleavage guided by the U7 snRNP that binds downstream of the cleavage site. Following cleavage, the downstream cleavage product (DCP) is rapidly degraded in vitro by a nuclease that also depends on the U7 snRNP. Our previous studies demonstrated that the endonucleolytic cleavage is catalyzed by the cleavage/polyadenylation factor CPSF-73.

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