Thousands of novel transcripts have been identified using deep transcriptome sequencing. This discovery of large and ‘hidden’ transcriptome rejuvenates the demand for methods that can rapidly distinguish between coding and noncoding RNA. Here, we present a novel alignment-free method, Coding Potential Assessment Tool (CPAT), which rapidly recognizes coding and noncoding transcripts from a large pool of candidates. To this end, CPAT uses a logistic regression model built with four sequence features: open reading frame size, open reading frame coverage, Fickett TESTCODE statistic and hexamer usage bias. CPAT software outperformed (sensitivity: 0.96, specificity: 0.97) other state-of-the-art alignment-based software such as Coding-Potential Calculator (sensitivity: 0.99, specificity: 0.74) and Phylo Codon Substitution Frequencies (sensitivity: 0.90, specificity: 0.63). In addition to high accuracy, CPAT is approximately four orders of magnitude faster than Coding-Potential Calculator and Phylo Codon Substitution Frequencies, enabling its users to process thousands of transcripts within seconds. The software accepts input sequences in either FASTA- or BED-formatted data files. We also developed a web interface for CPAT that allows users to submit sequences and receive the prediction results almost instantly.
Bromodomain and extraterminal domain (BET) protein inhibitors are emerging as promising anti-cancer therapies. The gene encoding the E3 ubiquitin ligase substrate-binding adaptor speckle-type POZ protein (SPOP) is most frequently mutated in prostate cancer. Here we demonstrate that wild-type SPOP binds to and induces ubiquitination and proteasomal degradation of BET proteins (BRD2, BRD3 and BRD4) by recognizing a common degron motif. In contrast, prostate cancer-associated SPOP mutants impair binding and proteasomal degradation of BET proteins, thus inducing their accumulation in prostate cancer cells and patient specimens. Transcriptome and BRD4 cistrome analyses reveal that SPOP mutation enhances BRD4-dependent expression of GTPase RAC1 and cholesterol biosynthesis genes and AKT-mTORC1 activation. SPOP mutant expression confers BET inhibitor resistance and this effect can be overcome by AKT inhibitors. Thus, SPOP mutations promote AKT-mTORC1 activation and intrinsic BET inhibitor resistance by stabilizing BET proteins, suggesting that SPOP mutation can be an effective biomarker to guide BET inhibitor-oriented therapy of prostate cancer.
The proneural, basic helix-loop-helix transcription factor Atoh1 governs the development of numerous key neuronal subtypes, such as cerebellar granule and brainstem neurons, inner ear hair cells, and several neurons of the proprioceptive system, as well as diverse nonneuronal cell types, such as Merkel cells and intestinal secretory lineages. However, the mere handful of targets that have been identified barely begin to account for Atoh1's astonishing range of functions, which also encompasses seemingly paradoxical activities, such as promoting cell proliferation and medulloblastoma formation in the cerebellum and inducing cell cycle exit and suppressing tumorigenesis in the intestine. We used a multipronged approach to create a comprehensive, unbiased list of over 600 direct Atoh1 target genes in the postnatal cerebellum. We found that Atoh1 binds to a 10 nucleotide motif (AtEAM) to directly regulate genes involved in migration, cell adhesion, metabolism, and other previously unsuspected functions. This study expands current thinking about the transcriptional activities driving neuronal differentiation and provides a framework for further neurodevelopmental studies.transcriptional regulation | chromatin immunoprecipitation | deep sequencing | E-box motif
Highlights d Voltage shifting and disulfide locking capture a resting-state structure of Na V Ab d Three gating charges translocate intracellularly through transmembrane electric field d Voltage sensor couples to pore opening by an elbow connecting S4 to the S4-S5 linker d Resting-state structure supports a sliding helix mechanism of gating
Mineralisation of fibrillar collagen with biomimetic process-directing agents has enabled scientists to gain insight into the potential mechanisms involved in intrafibrillar mineralisation. Here, by using polycation- and polyanion-directed intrafibrillar mineralisation, we challenge the popular paradigm that electrostatic attraction is solely responsible for polyelectrolyte-directed intrafibrillar mineralisation. Because there is no difference when a polycationic or a polyanionic electrolyte is used to direct collagen mineralisation, we argue that additional types of long-range non-electrostatic interactions are responsible for intrafibrillar mineralisation. Molecular dynamics simulations of collagen structures in the presence of extrafibrillar polyelectrolytes show that the outward movement of ions and intrafibrillar water through the collagen surface occurs irrespective of the charges of polyelectrolytes, resulting in the experimentally verifiable contraction of the collagen structures. The need to balance electroneutrality and osmotic equilibrium simultaneously to establish Gibbs-Donnan equilibrium in a polyelectrolyte-directed mineralisation system establishes a new model for collagen intrafibrillar mineralisation that supplements existing collagen mineralisation mechanisms.
LRP5 and LRP6 are Wnt co-receptors essential for Wnt/β-catenin signaling. DKK1 inhibits Wnt signaling by interacting with the extracellular domain of LRP5/6, and is a drug target for multiple diseases. Here we present the crystal structures of the first and second halves of LRP6’s four propeller–EGF pairs (LRP6-E1E2 and LRP6-E3E4), and a LRP6-E3E4/DKK1 complex. Combined with EM analysis, these data demonstrate that LRP6-E1E2 and LRP6-E3E4 form two rigid structural blocks, with a short intervening hinge that restrains their relative orientation. DKK1c interacts with the top surface of the LRP6-E3 YWTD propeller, and likely also that of the LRP6-E1 propeller due to structural similarity, through conserved hydrophobic patches buttressed by a network of salt bridges and hydrogen bonds. Our work provides key insights for understanding LRP5/6 structure and the interaction of LRP5/6 with DKK, as well as for drug discovery.
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