Intrahepatic cholangiocarcinoma (ICC) is a fatal primary liver cancer (PLC) that affects 5–10% of all PLCs. Here we sequence tumour and matching control sample pairs of a large cohort of 103 ICC patients in China, resulting in the identification of an ICC-specific somatic mutational signature that is associated with liver inflammation, fibrosis and cirrhosis. We further uncover 25 significantly mutated genes including eight potential driver genes (TP53, KRAS, IDH1, PTEN, ARID1A, EPPK1, ECE2 and FYN). We find that TP53-defective ICC patients are more likely to be HBsAg-seropositive, whereas mutations in the oncogene KRAS are nearly exclusively found in HBsAg-seronegative ICC patients. Three pathways (Ras/phosphatidylinositol-4,5-bisphosphate 3-kinase signalling, p53/cell cycle signalling and transforming growth factor-β/Smad signalling), genes important for epigenetic regulation and oxidative phosphorylation are substantially affected in ICC. We reveal mutations in this study that may be valuable for designing further studies, better diagnosis and effective therapies.

Background: The Amoebozoa constitute one of the primary divisions of eukaryotes, encompassing taxa of both biomedical and evolutionary importance, yet its genomic diversity remains largely unsampled. Here we present an analysis of a whole genome assembly of Acanthamoeba castellanii (Ac) the first representative from a solitary free-living amoebozoan. Results: Ac encodes 15,455 compact intron-rich genes, a significant number of which are predicted to have arisen through inter-kingdom lateral gene transfer (LGT). A majority of the LGT candidates have undergone a substantial degree of intronization and Ac appears to have incorporated them into established transcriptional programs. Ac manifests a complex signaling and cell communication repertoire, including a complete tyrosine kinase signaling toolkit and a comparable diversity of predicted extracellular receptors to that found in the facultatively multicellular dictyostelids. An important environmental host of a diverse range of bacteria and viruses, Ac utilizes a diverse repertoire of predicted pattern recognition receptors, many with predicted orthologous functions in the innate immune systems of higher organisms. Conclusions: Our analysis highlights the important role of LGT in the biology of Ac and in the diversification of microbial eukaryotes. The early evolution of a key signaling facility implicated in the evolution of metazoan multicellularity strongly argues for its emergence early in the Unikont lineage. Overall, the availability of an Ac genome should aid in deciphering the biology of the Amoebozoa and facilitate functional genomic studies in this important model organism and environmental host.

BLAST is an extensively used local similarity search tool for identifying homologous sequences. When a gene sequence (either protein sequence or nucleotide sequence) is used as a query to search for homologous sequences in a genome, the search results, represented as a list of high-scoring pairs (HSPs), are fragments of candidate genes rather than full-length candidate genes. Relevant HSPs (“signals”), which represent candidate genes in the target genome sequences, are buried within a report that contains also hundreds to thousands of random HSPs (“noises”). Consequently, BLAST results are often overwhelming and confusing even to experienced users. For effective use of BLAST, a program is needed for extracting relevant HSPs that represent candidate homologous genes from the entire HSP report. To achieve this goal, we have designed a graph-based algorithm, genBlastA, which automatically filters HSPs into well-defined groups, each representing a candidate gene in the target genome. The novelty of genBlastA is an edge length metric that reflects a set of biologically motivated requirements so that each shortest path corresponds to an HSP group representing a homologous gene. We have demonstrated that this novel algorithm is both efficient and accurate for identifying homologous sequences, and that it outperforms existing approaches with similar functionalities.

The large and complex hexaploid genome has greatly hindered genomics studies of common wheat (Triticum aestivum, AABBDD). Here, we investigated transcripts in common wheat developing caryopses using the emerging single-molecule real-time (SMRT) sequencing technology PacBio RSII, and assessed the resultant data for improving common wheat genome annotation and grain transcriptome research. We obtained 197,709 full-length non-chimeric (FLNC) reads, 74.6 % of which were estimated to carry complete open reading frame. A total of 91,881 high-quality FLNC reads were identified and mapped to 16,188 chromosomal loci, corresponding to 13,162 known genes and 3026 new genes not annotated previously. Although some FLNC reads could not be unambiguously mapped to the current draft genome sequence, many of them are likely useful for studying highly similar homoeologous or paralogous loci or for improving chromosomal contig assembly in further research. The 91,881 high-quality FLNC reads represented 22,768 unique transcripts, 9591 of which were newly discovered. We found 180 transcripts each spanning two or three previously annotated adjacent loci, suggesting that they should be merged to form correct gene models. Finally, our data facilitated the identification of 6030 genes differentially regulated during caryopsis development, and full-length transcripts for 72 transcribed gluten gene members that are important for the end-use quality control of common wheat. Our work demonstrated the value of PacBio transcript sequencing for improving common wheat genome annotation through uncovering the loci and full-length transcripts not discovered previously. The resource obtained may aid further structural genomics and grain transcriptome studies of common wheat.

Background: Five regulatory factor X (RFX) transcription factors (TFs)–RFX1-5–have been previously characterized in the human genome, which have been demonstrated to be critical for development and are associated with an expanding list of serious human disease conditions including major histocompatibility (MHC) class II deficiency and ciliaophathies. Results: In this study, we have identified two additional RFX genes–RFX6 and RFX7–in the current human genome sequences. Both RFX6 and RFX7 are demonstrated to be winged-helix TFs and have well conserved RFX DNA binding domains (DBDs), which are also found in winged-helix TFs RFX1-5. Phylogenetic analysis suggests that the RFX family in the human genome has undergone at least three gene duplications in evolution and the seven human RFX genes can be clearly categorized into three subgroups: (1) RFX1-3, (2) RFX4 and RFX6, and (3) RFX5 and RFX7. Our functional genomics analysis suggests that RFX6 and RFX7 have distinct expression profiles. RFX6 is expressed almost exclusively in the pancreatic islets, while RFX7 has high ubiquitous expression in nearly all tissues examined, particularly in various brain tissues. Conclusion: The identification and further characterization of these two novel RFX genes hold promise for gaining critical insight into development and many disease conditions in mammals, potentially leading to identification of disease genes and biomarkers.

Motivation: BLAST users frequently expect to obtain homologous genes with certain similarity to their query genes. But what they get from BLAST searches are often collections of local alignments called high-scoring segment pairs (HSPs). On the other hand, most homology-based gene finders have been built using computation-intensive algorithms, without taking full advantage of BLAST searches that have been perfected over the last decades. Results: Here we report an efficient algorithm, genBlastG that directly uses the HSPs reported by BLAST to define high-quality gene models. Availability:http://genome.sfu.ca/genblast/download.html Contact:chenn@sfu.ca Supplementary information: Supplementary data are available at Bioinformatics online.