Third generation single molecule sequencing technology is poised to revolutionize genomics by enabling the sequencing of long, individual molecules of DNA and RNA. These technologies now routinely produce reads exceeding 5,000 basepairs, and can achieve reads as long as 50,000 basepairs. Here we evaluate the limits of single molecule sequencing by assessing the impact of long read sequencing in the assembly of the human genome and 25 other important genomes across the tree of life. From this, we develop a new data-driven model using support vector regression that can accurately predict assembly performance. We also present a novel hybrid error correction algorithm for long PacBio sequencing reads that uses pre-assembled Illumina sequences for the error correction. We apply it several prokaryotic and eukaryotic genomes, and show it can achieve near-perfect assemblies of small genomes (< 100Mbp) and substantially improved assemblies of larger ones. All source code and the assembly model are available open-source.
Third-generation long-range DNA sequencing and mapping technologies are creating a renaissance in high-quality genome sequencing. Unlike second-generation sequencing, which produces short reads a few hundred base-pairs long, third-generation single-molecule technologies generate over 10,000 bp reads or map over 100,000 bp molecules. We analyze how increased read lengths can be used to address longstanding problems in de novo genome assembly, structural variation analysis and haplotype phasing.
α-Actinin-4 (ACTN4) is frequently amplified and overexpressed in various cancers. Although ACTN4 functions in cancer cell migration and invasion, the roles of ACTN4 during the epithelial-to-mesenchymal transition (EMT) and cervical cancer tumorigenesis are unknown. In this study, we investigated the function of ACTN4 in the progression of cervical cancer and the mechanisms of EMT and tumorigenesis induced by ACTN4. We found that ACTN4 induced EMT by upregulating Snail, which was dependent on the Akt signaling pathway in cervical cancer. ACTN4 induced cell migration and invasion through Snail-mediated matrix metalloproteinase-9 expression. ACTN4 expression level was correlated with stabilization of β-catenin. Accumulatioin of β-catenin owing to ACTN4 induced tumorigenesis via upregulation of genes involved in cell proliferation, including cyclin D1 and c-myc. ACTN4 knockdown reduced cervical cancer cell proliferation and tumor formation in vivo. The expression level of ACTN4 is highly elevated in human cervical tumors, compared with that in normal cervical tissues. ACTN4-overexpressing MDCK cells induced tumor formation and metastatic nodules in nude mice. Our findings indicate that ACTN4 promotes EMT and tumorigenesis by regulating Snail expression and the Akt pathway in cervical cancer. We propose a novel mechanism for EMT and tumorigenesis in cervical cancer.
17The U.S. Department of Energy Systems Biology Knowledgebase (KBase) is an open-source 18 software and data platform designed to meet the grand challenge of systems biology-19 predicting and designing biological function from the biomolecular (small scale) to the ecological 20 (large scale). KBase is available for anyone to use, and enables researchers to collaboratively 21 generate, test, compare, and share hypotheses about biological functions; perform large-scale 22 analyses on scalable computing infrastructure; and combine experimental evidence and 23conclusions that lead to accurate models of plant and microbial physiology and community 24 dynamics. The KBase platform has (1) extensible analytical capabilities that currently include 25 genome assembly, annotation, ontology assignment, comparative genomics, transcriptomics, 26 and metabolic modeling; (2) a web-browser-based user interface that supports building, sharing, 27and publishing reproducible and well-annotated analyses with integrated data; (3) access to 28 extensive computational resources; and (4) a software development kit allowing the community 29to add functionality to the system. 30
This study reports the physical and functional interplay between Fas-associated factor 1 (FAF1), a death-promoting protein, and parkin, a key susceptibility protein for Parkinson's disease (PD). We found that parkin acts as an E3 ubiquitin ligase to ubiquitinate FAF1 both in vitro and at cellular level, identifying FAF1 as a direct substrate of parkin. The loss of parkin function due to PD-linked mutations was found to disrupt the ubiquitination and degradation of FAF1, resulting in elevated FAF1 expression in SH-SY5Y cells. Moreover, FAF1-mediated cell death was abolished by wild-type parkin, but not by PD-linked parkin mutants, implying that parkin antagonizes the death potential of FAF1. This led us to investigate whether FAF1 participates in the pathogenesis of PD. To address this, we used a gene trap mutagenesis approach to generate mutant mice with diminished levels of FAF1 (Faf1(gt/gt)). Using the 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-treated mouse model of PD, we found that FAF1 accumulated in the substantia nigra pars compacta (SNc) of MPTP-treated PD mice, and that MPTP-induced dopaminergic cell loss in the SNc was significantly attenuated in Faf1(gt/gt) mice versus Faf1(+/+) mice. MPTP-induced reduction of locomotor activity was also lessened in Faf1(gt/gt) mice versus Faf1(+/+) mice. Furthermore, we found that FAF1 deficiency blocked PD-linked biochemical events, including caspase activation, ROS generation, JNK activation and cell death. Taken together, these results suggest a new role for FAF1: that of a positive modulator for PD.
We put forward the hypothesis that TGF-beta1 is mainly produced by MFBs and macrophages at early and middle stages of fibrotic processes, but it is predominantly released by hypoxic hepatocytes in the last fibrotic stage or cirrhosis.
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