A 3’-end capture sequencing method for high-throughput targeted gene expression profiling

Molecular phenotyping through shallow 3’-end RNA-sequencing workflows is increasingly applied in the context of large-scale chemical or genetic perturbation screens to study disease biology or support drug discovery. While these workflows enable accurate quantification of the most abundant genes, they are less effective for applications that require expression profiling of low abundant transcripts, like long non-coding RNAs (lncRNAs), or selected gene panels. To tackle these issues, we describe a workflow combining 3’-end library preparation with 3’-end hybrid capture probes and shallow RNA-sequencing for cost-effective, targeted quantification of subsets of (low abundant) genes across hundreds to thousands of samples. To assess the performance of the method, we designed a capture probe set for more than 100 mRNA and lncRNA target genes and applied the workflow to a cohort of 360 samples. When compared to standard 3’-end RNA-sequencing, 3’-end capture sequencing resulted in a more than 100-fold enrichment of target gene abundance while conserving relative inter-gene and inter-sample abundances. 3’-end RNA capture sequencing enables accurate targeted gene expression profiling at extremely shallow sequencing depth.

A customised target capture sequencing tool for molecular identification of Aloe vera and relatives

Plant molecular identification studies have, until recently, been limited to the use of highly conserved markers from plastid and other organellar genomes, compromising resolution in highly diverse plant clades. Due to their higher evolutionary rates and reduced paralogy, low-copy nuclear genes overcome this limitation but are difficult to sequence with conventional methods and require high-quality input DNA. Aloe vera and its relatives in the Alooideae clade (Asphodelaceae, subfamily Asphodeloideae) are of economic interest for food and health products and have horticultural value. However, pressing conservation issues are increasing the need for a molecular identification tool to regulate the trade. With > 600 species and an origin of ± 15 million years ago, this predominantly African succulent plant clade is a diverse and taxonomically complex group for which low-copy nuclear genes would be desirable for accurate species discrimination. Unfortunately, with an average genome size of 16.76 pg, obtaining high coverage sequencing data for these genes would be prohibitively costly and computationally demanding. We used newly generated transcriptome data to design a customised RNA-bait panel targeting 189 low-copy nuclear genes in Alooideae. We demonstrate its efficacy in obtaining high-coverage sequence data for the target loci on Illumina sequencing platforms, including degraded DNA samples from museum specimens, with considerably improved phylogenetic resolution. This customised target capture sequencing protocol has the potential to confidently indicate phylogenetic relationships of Aloe vera and related species, as well as aid molecular identification applications.

Overlap phenotypes of the left ventricular noncompaction and hypertrophic cardiomyopathy with complex arrhythmias and heart failure induced by the novel truncated DSC2 mutation

Background The left ventricular noncompaction cardiomyopathy (LVNC) is a rare subtype of cardiomyopathy associated with a high risk of heart failure (HF), thromboembolism, arrhythmia, and sudden cardiac death. Methods The proband with overlap phenotypes of LVNC and hypertrophic cardiomyopathy (HCM) complicates atrial fibrillation (AF), ventricular tachycardia (VT), and HF due to the diffuse myocardial lesion, which were diagnosed by electrocardiogram, echocardiogram and cardiac magnetic resonance imaging. Peripheral blood was collected from the proband and his relatives. DNA was extracted from the peripheral blood of proband for high-throughput target capture sequencing. The Sanger sequence verified the variants. The protein was extracted from the skin of the proband and healthy volunteer. The expression difference of desmocollin2 was detected by Western blot. Results The novel heterozygous truncated mutation (p.K47Rfs*2) of the DSC2 gene encoding an important component of desmosomes was detected by targeted capture sequencing. The western blots showed that the expressing level of functional desmocollin2 protein (~ 94kd) was lower in the proband than that in the healthy volunteer, indicating that DSC2 p.K47Rfs*2 obviously reduced the functional desmocollin2 protein expression in the proband. Conclusion The heterozygous DSC2 p.K47Rfs*2 remarkably and abnormally reduced the functional desmocollin2 expression, which may potentially induce the overlap phenotypes of LVNC and HCM, complicating AF, VT, and HF.

Der(1;7)(q10;p10) Presents with a Unique Genetic Profile and Frequent ETNK1 Mutations in Myeloid Neoplasms

Background Der(1;7)(q10;p10) (der(1;7) is an unbalanced translocation recurrently found in myeloid neoplasms, particularly in myelodysplastic syndromes (MDS) and related disorders. Caused by a recombination between two homologous alphoid sequencing D1Z7 and D7Z1 on chromosomes 1 and 7, respectively, it results in monosomy 7q and trisomy 1q, which is implicated in the pathogenesis of der(1;7)-positive myeloid neoplasms. Previous studies reported frequent co-occurrence of +8 and del(20q), as well as RUNX1 mutations, the genetic and clinical characteristics of this abnormality has not fully been elucidated. Methods In this study, we enrolled a total of 153 cases myeloid neoplasms positive for der(1;7) from Japanese and German cohorts, in which co-occurring genetic lesions were analyzed using whole exome and/or targeted-capture sequencing. An additional 3,223 MDS and related neoplasm cases were also analyzed using targeted-capture sequencing to identify der(1;7)-specific genomic features. Results Ethnicity was evaluated comparing the frequency of der(1;7) in 944 German MDS cases and 763 Japanese MDS cases. Der(1;7) cases were observed at a higher frequency in Japanese MDS cohort compared to German MDS cohort (73/763 cases versus 4/944 cases, p < 0.00001). Der(1;7) cases showed a strong male predominance (86.3%) (p<0.001). Of 153 myeloid neoplasm patients harboring der(1;7), 114 were diagnosed with MDS, 28 with AML, 5 with MDS-MPN and 1 with MPN. Targeted-capture sequencing revealed mutations in common myeloid drivers (n=61) in 96% of der(1;7) cases. The most frequently mutated gene was RUNX1 with 46%, followed by ETNK1 (24.5%) and EZH2 (24.5%). Of interest, ETNK1 mutation was identified as the most unique to der(1;7) when compared to myeloid neoplasm cases without der(1;7) (n=3,066) [odds ratio (OR)=15.06], followed by ETV6 (OR=9.35) and EZH2 (OR=6.52). To further examine the uniqueness of this mutation profile, the mutational profile of der(1;7) was compared to those myeloid neoplasm cases harboring amp(1q) (n=52) and monosomy 7 (n=105). Highly frequent ETV6 and ETNK1 mutations were highly unique to der(1;7) cases when compared to amp(1q) cases (OR=3.72, OR=2.57, respectively). BCOR and ETNK1 mutations were highly unique to der(1;7) cases when compared to monosomy 7 cases (OR=35.88, OR=4.29, respectively). Both amp(1q) and monosomy 7 cases showed a higher mutation rate in TP53 compared to der(1;7) cases (49.1% and 51%, respectively, vs 3.5 %) . From these mutational characteristics, ETNK1 was identified as being the most unique to der(1;7) when compared to amp(1q), monosomy 7 and other myeloid neoplasm cases. ETNK1-mutated der(1;7) cases were featured with eosinophilia (p < 0.0005), a lack of RAS pathway mutations and trisomy 8 when compared to ETNK1-wild type der(1;7) cases. Survival analysis was conducted to elucidate the difference in survival in der(1;7) cases (n=65) versus myeloid neoplasm cases (n=2066). Der(1;7)-harboring myeloid neoplasm cases had a median overall survival of 6.8 months (95% CI, 3.5 to 11.9) and non-der(1;7) harboring myeloid neoplasm cases were 11.8 months (95% CI, 10.5 to 12.6). Thus, der(1;7)-harboring myeloid neoplasm cases had poorer prognosis (p<0.001). Conclusion In conclusion, der(1;7) is an unbalanced translocation that occurs predominantly in males and is seen more frequently in Japanese than Caucasian populations. Der(1;7) cases present with a mutational profile that is distinct from other myeloid neoplasm cases such as those with amp(1q) and monosomy7/del(7q), showing frequency of ETNK1 mutations. Disclosures Nannya: Otsuka Pharmaceutical Co., Ltd.: Consultancy, Speakers Bureau; Astellas: Speakers Bureau. Kern: MLL Munich Leukemia Laboratory: Other: Part ownership. Haferlach: MLL Munich Leukemia Laboratory: Other: Part ownership. Atsuta: Astellas Pharma Inc.: Speakers Bureau; Mochida Pharmaceutical Co., Ltd.: Speakers Bureau; AbbVie GK: Speakers Bureau; Kyowa Kirin Co., Ltd: Honoraria; Meiji Seika Pharma Co, Ltd.: Honoraria. Handa: Ono: Honoraria; BMS: Honoraria; Janssen: Honoraria; Daiichi Sankyo: Research Funding; Celgene: Honoraria, Research Funding; Chugai: Research Funding; Kyowa Kirin: Research Funding; Takeda: Honoraria, Research Funding; Sanofi: Honoraria, Research Funding; Abbvie: Honoraria; MSD: Research Funding; Shionogi: Research Funding. Ohyashiki: Novartis Pharma: Other: chief clinical trial; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees. Haferlach: MLL Munich Leukemia Laboratory: Other: Part ownership. Ogawa: Otsuka Pharmaceutical Co., Ltd.: Research Funding; Eisai Co., Ltd.: Research Funding; Kan Research Laboratory, Inc.: Consultancy, Research Funding; Dainippon-Sumitomo Pharmaceutical, Inc.: Research Funding; ChordiaTherapeutics, Inc.: Consultancy, Research Funding; Ashahi Genomics: Current holder of individual stocks in a privately-held company.

Transcriptome Capture Sequencing Method_The Broad Institute v1

Here we describe the Transcriptome Capture Method followed by The Broad Genomics Platform for sequencing bulk RNA from human biospecimens for the Human Atlas Pilot Project (HTAPP). This protocol is usually utilized for Formalin Fixed Paraffin Embedded (FFPE) samples, although it can also be used for non-FFPE samples, as was the case for some HTAPP samples.

The Effects and Underlying Mechanisms of Hepatitis B Virus X Gene Mutants on the Development of Hepatocellular Carcinoma

Background: We aimed to elucidate the mechanism by which hepatitis B virus X (HBx) gene mutations increase the risk of hepatocellular carcinoma (HCC) and identify novel therapeutic targets.Methods: Wild-type and four HBx mutants (M1, A1762T/G1764A; M2, T1674G+T1753C+A1762T/G1764A; M3, C1653T+T1674G+A1762T/G1764A; Ct-HBx, carboxylic acid-terminal truncated HBx) were delivered into the livers of fumarylacetoacetate hydrolase-deficient mice by using the Sleeping Beauty (SB) transposon system, respectively. Seven liver tissues and seven tumor tissues of the SB mouse models were subjected to HBV-capture sequencing. Three liver tissues from WT-HBx mice, three tumor tissues from M3-HBx mice, and three tumor tissues from Ct-HBx mice were subjected to cDNA microarray analysis. HeLa cells stably expressing WT-HBx and the four HBx mutants were also subjected to cDNA microarray assay.Results: The incidence of HCC was higher in the mice injected with M3-HBx or Ct-HBx. M3-HBx had a stronger capacity of upregulating inflammatory cytokines than other HBx variants. HBV-capture sequencing showed that the HBx fragments were mainly integrated into intergenic and intron regions. No significant difference was observed in the number of insertion sites between tumors and liver tissues. Ectopic expression of the HBx mutants, especially M3-HBx and Ct-HBx, significantly increased cell proliferation and the S phase proportion of HepG2 and HeLa cells, compared to WT-HBx. Liver tissues of the SB mice and the transfected cells were subjected to cDNA microarray analysis. Plasminogen activator inhibitor-1 (PAI1) and cell division cycle 20 (CDC20) were identified as novel effectors. M3-HBx and Ct-HBx significantly upregulated the expression of PAI1 and CDC20 in HepG2 and HeLa cells as well as the livers of the SB mice. PAI1 silencing attenuated the effect of M3-HBx and Ct-HBx on the growth of HepG2 cells and greatly decreased the growth of HeLa cells with Ct-HBx. Conclusion: HBx C1653T+T1674G+A1762T/G1764A mutant and Ct-HBx promote carcinogenesis via upregulating PAI1 and CDC20. PAI1, an important player bridging the HBx mutants and HCC, should be a promising candidate as a predictive and prognostic biomarker and therapeutic target in HBV-related HCC.

Oligonucleotide capture sequencing of the SARS-CoV-2 genome and subgenomic fragments from COVID-19 individuals

The newly emerged and rapidly spreading SARS-CoV-2 causes coronavirus disease 2019 (COVID-19). To facilitate a deeper understanding of the viral biology we developed a capture sequencing methodology to generate SARS-CoV-2 genomic and transcriptome sequences from infected patients. We utilized an oligonucleotide probe-set representing the full-length genome to obtain both genomic and transcriptome (subgenomic open reading frames [ORFs]) sequences from 45 SARS-CoV-2 clinical samples with varying viral titers. For samples with higher viral loads (cycle threshold value under 33, based on the CDC qPCR assay) complete genomes were generated. Analysis of junction reads revealed regions of differential transcriptional activity among samples. Mixed allelic frequencies along the 20kb ORF1ab gene in one sample, suggested the presence of a defective viral RNA species subpopulation maintained in mixture with functional RNA in one sample. The associated workflow is straightforward, and hybridization-based capture offers an effective and scalable approach for sequencing SARS-CoV-2 from patient samples.