DNA G-quadruplex profiling in skeletal muscle stem cells reveals functional and mechanistic insights.

Background: DNA G-quadruplexes (G4s) are non-canonical secondary structures formed in guanine-rich DNA sequences and play important roles in modulating biological processes through a variety of gene regulatory mechanisms. Emerging G4 profiling allows global mapping of endogenous G4 formation.

Results: Here in this study, we map the G4 landscapes in adult skeletal muscle stem cells (MuSCs), which are essential for injury-induced muscle regeneration.

Endophytic bacteria enhance cadmium remediation through siderophore production and soil microbial dynamics.

Microbial remediation of heavy metals (HMs) is an environmentally friendly and cost-effective approach to soil restoration. This study aimed to identify the endophytic bacterial strain with the highest capacity to mobilize cadmium (Cd) among four isolates from root nodules. We conducted soil incubation experiments under four Cd contamination levels (10, 40, 80 and 300 mg kg) and three inoculation treatments, and measured soil extractable Cd, microbial community composition, and diversity.

Structural basis of RECQL5-induced RNA polymerase II transcription braking and subsequent reactivation.

Abnormally fast transcription elongation can lead to detrimental consequences such as transcription-replication collisions, altered alternative splicing patterns and genome instability. Therefore, elongating RNA polymerase II (Pol II) requires mechanisms to slow its progression, yet the molecular basis of transcription braking remains unclear. RECQL5 is a DNA helicase that functions as a general elongation factor by slowing down Pol II.

Structure of a transcribing Pol II-DSIF-SPT6-U1 snRNP complex.

In eukaryotic cells, splicing occurs predominantly co-transcriptionally, enhancing splicing efficiency and fidelity while introducing an additional layer of regulation over gene expression. RNA polymerase II (Pol II) facilitates co-transcriptional splicing by recruiting the U1 small nuclear ribonucleoprotein particle (U1 snRNP) to the nascent transcripts. Here, we report the cryo-electron microscopy structure of a transcribing Pol II-U1 snRNP complex with elongation factors DSIF and SPT6.

Unspliced XBP1 enhences metabolic reprogramming in colorectal cancer cells by interfering with the mitochondrial localization of MGME1.

Tumor cells undergo metabolic reprogramming, which makes them tend to utilize anaerobic glycolysis rather than oxidation to rapidly produce energy and intermediate products required for proliferation. In this process, mitochondria inevitably undergo corresponding alterations; however, the specific alterations in mitochondria across different cancer types and the mechanisms governing these changes remain poorly understood. This study demonstrated that unspliced X-box binding protein 1 (XBP1-u) inhibits the translocation of mitochondrial genome maintenance exonuclease 1 (MGME1) into mitochondria by binding to the mitochondrial targeting sequence (MTS) of MGME1.

ATF3 induction prevents precocious activation of skeletal muscle stem cell by regulating H2B expression.

Skeletal muscle stem cells (also called satellite cells, SCs) are important for maintaining muscle tissue homeostasis and damage-induced regeneration. However, it remains poorly understood how SCs enter cell cycle to become activated upon injury. Here we report that AP-1 family member ATF3 (Activating Transcription Factor 3) prevents SC premature activation.

seRNA PAM controls skeletal muscle satellite cell proliferation and aging through trans regulation of Timp2 expression synergistically with Ddx5.

Muscle satellite cells (SCs) are responsible for muscle homeostasis and regeneration and lncRNAs play important roles in regulating SC activities. Here, in this study, we identify PAM (Pax7 Associated Muscle lncRNA) that is induced in activated/proliferating SCs upon injury to promote SC proliferation as myoblast cells. PAM is generated from a myoblast-specific super-enhancer (SE); as a seRNA it binds with a number of target genomic loci predominantly in trans.

Lockd promotes myoblast proliferation and muscle regeneration via binding with DHX36 to facilitate 5' UTR rG4 unwinding and Anp32e translation.

Adult muscle stem cells, also known as satellite cells (SCs), play pivotal roles in muscle regeneration, and long non-coding RNA (lncRNA) functions in SCs remain largely unknown. Here, we identify a lncRNA, Lockd, which is induced in activated SCs upon acute muscle injury. We demonstrate that Lockd promotes SC proliferation; deletion of Lockd leads to cell-cycle arrest, and in vivo repression of Lockd in mouse muscles hinders regeneration process.

Discovery and Validation of a Novel Target of Molluscicides against Oncomelania hupensis, the Intermediate Host of Schistosoma japonicum.

In this study, 196 strains of actinomycetes isolated from marshland soil samples were tested for molluscicidal activity against Oncomelania hupensis. Five strains demonstrated molluscicidal activity, of which the molluscicidal efficiency of Actinomycetes strain A183 was the maximum. After the fermentation supernatant of actinomycetes A183 was extracted with ethyl acetate (EWEA), the LC50 of the EWEA after leaching for 48 h and 72 h were 0.

Structure of a transcribing RNA polymerase II-U1 snRNP complex.

To initiate cotranscriptional splicing, RNA polymerase II (Pol II) recruits the U1 small nuclear ribonucleoprotein particle (U1 snRNP) to nascent precursor messenger RNA (pre-mRNA). Here, we report the cryo-electron microscopy structure of a mammalian transcribing Pol II-U1 snRNP complex. The structure reveals that Pol II and U1 snRNP interact directly.

Long noncoding RNA SAM promotes myoblast proliferation through stabilizing Sugt1 and facilitating kinetochore assembly.

The functional study of lncRNAs in skeletal muscle satellite cells (SCs) remains at the infancy stage. Here we identify SAM (Sugt1 asssociated muscle) lncRNA that is enriched in the proliferating myoblasts. Global deletion of SAM has no overt effect on mice but impairs adult muscle regeneration following acute damage; it also exacerbates the chronic injury-induced dystrophic phenotype in mdx mice.

Cyclin A2 degradation during the spindle assembly checkpoint requires multiple binding modes to the APC/C.

The anaphase-promoting complex/cyclosome (APC/C) orchestrates cell cycle progression by controlling the temporal degradation of specific cell cycle regulators. Although cyclin A2 and cyclin B1 are both targeted for degradation by the APC/C, during the spindle assembly checkpoint (SAC), the mitotic checkpoint complex (MCC) represses APC/C's activity towards cyclin B1, but not cyclin A2. Through structural, biochemical and in vivo analysis, we identify a non-canonical D box (D2) that is critical for cyclin A2 ubiquitination in vitro and degradation in vivo.

Visualizing the complex functions and mechanisms of the anaphase promoting complex/cyclosome (APC/C).

The anaphase promoting complex or cyclosome (APC/C) is a large multi-subunit E3 ubiquitin ligase that orchestrates cell cycle progression by mediating the degradation of important cell cycle regulators. During the two decades since its discovery, much has been learnt concerning its role in recognizing and ubiquitinating specific proteins in a cell-cycle-dependent manner, the mechanisms governing substrate specificity, the catalytic process of assembling polyubiquitin chains on its target proteins, and its regulation by phosphorylation and the spindle assembly checkpoint. The past few years have witnessed significant progress in understanding the quantitative mechanisms underlying these varied APC/C functions.

MyoD- and FoxO3-mediated hotspot interaction orchestrates super-enhancer activity during myogenic differentiation.

Super-enhancers (SEs) are cis-regulatory elements enriching lineage specific key transcription factors (TFs) to form hotspots. A paucity of identification and functional dissection promoted us to investigate SEs during myoblast differentiation. ChIP-seq analysis of histone marks leads to the uncovering of SEs which remodel progressively during the course of differentiation.

LncFunNet: an integrated computational framework for identification of functional long noncoding RNAs in mouse skeletal muscle cells.

Long noncoding RNAs (lncRNAs) are key regulators of diverse cellular processes. Recent advances in high-throughput sequencing have allowed for an unprecedented discovery of novel lncRNAs. To identify functional lncRNAs from thousands of candidates for further functional validation is still a challenging task.

regulates myogenic differentiation and muscle regeneration through modulating MyoD transcriptional activity.

is one of the most abundant long non-coding RNAs in various cell types; its exact cellular function is still a matter of intense investigation. In this study we characterized the function of in skeletal muscle cells and muscle regeneration. Utilizing both and assays, we demonstrate that has a role in regulating gene expression during myogenic differentiation of myoblast cells.

Molecular mechanism of APC/C activation by mitotic phosphorylation.

In eukaryotes, the anaphase-promoting complex (APC/C, also known as the cyclosome) regulates the ubiquitin-dependent proteolysis of specific cell-cycle proteins to coordinate chromosome segregation in mitosis and entry into the G1 phase. The catalytic activity of the APC/C and its ability to specify the destruction of particular proteins at different phases of the cell cycle are controlled by its interaction with two structurally related coactivator subunits, Cdc20 and Cdh1. Coactivators recognize substrate degrons, and enhance the affinity of the APC/C for its cognate E2 (refs 4-6).

Systematic characterization of seminal plasma piRNAs as molecular biomarkers for male infertility.

Although piwi-interacting RNAs (piRNAs) play pivotal roles in spermatogenesis, little is known about piRNAs in the seminal plasma of infertile males. In this study, we systematically investigated the profiles of seminal plasma piRNAs in infertile males to identify piRNAs that are altered during infertility and evaluate their diagnostic value. Seminal plasma samples were obtained from 211 infertile patients (asthenozoospermia and azoospermia) and 91 fertile controls.

Linc-YY1 promotes myogenic differentiation and muscle regeneration through an interaction with the transcription factor YY1.

Little is known how lincRNAs are involved in skeletal myogenesis. Here we describe the discovery of Linc-YY1 from the promoter of the transcription factor (TF) Yin Yang 1 (YY1) gene. We demonstrate that Linc-YY1 is dynamically regulated during myogenesis in vitro and in vivo.

miR-16 promotes the apoptosis of human cancer cells by targeting FEAT.

Background: Although human cancers have heterogeneous combinations of altered oncogenes, some crucial genes are universally dysregulated in most cancers. One such gene, FEAT (faint expression in normal tissues, aberrant overexpression in tumors), is uniformly overexpressed in a variety of human cancers and plays an important role in tumorigenesis by suppressing apoptosis. However, the precise molecular mechanism through which FEAT is upregulated during tumorigenesis remains largely unknown.

microRNA-200b and microRNA-200c promote colorectal cancer cell proliferation via targeting the reversion-inducing cysteine-rich protein with Kazal motifs.

MicroRNA-200b and microRNA-200c (miR-200b/c) are 2 of the most frequently upregulated oncomiRs in colorectal cancer cells. The role of miR-200b/c during colorectal tumorigenesis, however, remains unclear. In the present study, we report that miR-200b/c can promote colorectal cancer cell proliferation via targeting the reversion-inducing cysteine-rich protein with Kazal motifs (RECK).

Effective detection and quantification of dietetically absorbed plant microRNAs in human plasma.

The detection of exogenous plant microRNAs in human/animal plasma/sera lies at the foundation of exploring their cross-kingdom regulatory functions. It is necessary to establish a standard operation procedure to promote study in this nascent field. In this study, 18 plant miRNAs were assessed in watermelon juice and mixed fruits by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR).