Case Report: BMPR2-Targeted MinION Sequencing as a Tool for Genetic Analysis in Patients With Pulmonary Arterial Hypertension

Background: Mutations in the bone morphogenetic protein receptor type 2 gene (BMPR2) represent a major genetic cause of pulmonary arterial hypertension (PAH). Identification of BMPR2 mutations is crucial for the genetic diagnosis of PAH. MinION nanopore sequencer is a portable third-generation technology that enables long-read sequencing at a low-cost. This nanopore technology-based device has not been used previously for PAH diagnosis. This study aimed to determine the feasibility of using MinION nanopore sequencing for the genetic analysis of PAH patients, focused on BMPR2.Methods: We developed a protocol for the custom bioinformatics pipeline analysis of long reads generated by long-PCR. To evaluate the potential of using MinION sequencing in PAH, we analyzed five samples, including those of two idiopathic PAH patients and a family of three members with one affected patient. Sanger sequencing analysis was performed to validate the variants.Results: The median read length was around 3.4 kb and a good mean quality score of approximately 19 was obtained. The total number of reads generated was uniform among the cases and ranged from 2,268,263 to 3,126,719. The coverage was consistent across flow cells in which the average number of reads per base ranged from 80,375 to 135,603. We identified two polymorphic variants and three mutations in four out of five patients. Certain indel variant calling-related errors were observed, mostly outside coding sequences.Conclusion: We have shown the ability of this portable nanopore sequencer to detect BMPR2 mutations in patients with PAH. The MinION nanopore sequencer is a promising tool for screening BMPR2 mutations, especially in small laboratories and research groups.

Structure of bacterial communities in Japanese-style bathrooms: Comparative sequencing of bacteria in shower water and showerhead biofilms using a portable nanopore sequencer

Showers are one of the main exposure routes to diverse microbes for end users in built environments. Bacteria in water are responsible for biofilm formation on surfaces, and the inside of a showerhead is a specific niche. Here, for the purpose of microbial characterization, source estimation and possibility of infection, the bacterial compositions of both shower water and showerhead biofilms in the same bathroom were determined and compared using a portable nanopore sequencer. The results suggest that specific bacteria in source water would primarily adhere to the surface of the showerhead where they subsequently form biofilms, and the community compositions within biofilms largely vary depending on environmental factors. The relative abundance of several pathogenic bacterial genera in both water and biofilm samples was low. We suggest that it is important to manage risk of infection in each household, and rapid on-site analysis of microbial communities will allow the realization.

Multiplex PCR-Based Nanopore Sequencing and Epidemiological Surveillance of Hantaan orthohantavirus in Apodemus agrarius, Republic of Korea

Whole-genome sequencing of infectious agents enables the identification and characterization of emerging viruses. The MinION device is a portable sequencer that allows real-time sequencing in fields or hospitals. Hantaan orthohantavirus (Hantaan virus, HTNV), harbored by Apodemus agrarius, causes hemorrhagic fever with renal syndrome (HFRS) and poses a critical public health threat worldwide. In this study, we aimed to evaluate the feasibility of using nanopore sequencing for whole-genome sequencing of HTNV from samples having different viral copy numbers. Amplicon-based next-generation sequencing was performed in A. agrarius lung tissues collected from the Republic of Korea. Genomic sequences of HTNV were analyzed based on the viral RNA copy numbers. Amplicon-based nanopore sequencing provided nearly full-length genomic sequences of HTNV and showed sufficient read depth for phylogenetic analysis after 8 h of sequencing. The average identity of the HTNV genome sequences for the nanopore sequencer compared to those of generated from Illumina MiSeq revealed 99.8% (L and M segments) and 99.7% (S segment) identities, respectively. This study highlights the potential of the portable nanopore sequencer for rapid generation of accurate genomic sequences of HTNV for quicker decision making in point-of-care testing of HFRS patients during a hantavirus outbreak.

NanoSINC-seq dissects the isoform diversity in subcellular compartments of single cells

Alternative mRNA isoforms play a key role in generating diverse protein isoforms. To dissect isoform usage in the subcellular compartments of single cells, we introduced an novel approach, nanopore sequencing coupled with single-cell integrated nuclear and cytoplasmic RNA sequencing, that couples microfluidic fractionation, which separates cytoplasmic RNA from nuclear RNA, with full-length complementary DNA (cDNA) sequencing using a nanopore sequencer. Leveraging full-length cDNA reads, we found that the nuclear transcripts are notably more diverse than cytoplasmic transcripts. Our findings also indicated that transcriptional noise emanating from the nucleus is regulated across the nuclear membrane and then either attenuated or amplified in the cytoplasm depending on the function involved. Overall, our results provide the landscape that shows how the transcriptional noise arising from the nucleus propagates to the cytoplasm.

DAJIN-assisted multiplex genotyping to validate the outcomes of CRISPR-Cas-based genome editing

Genome editing induces various on-target mutations. Accurate identification of mutations in founder mice and cell clones is essential to perform reliable genome editing experiments. However, no genotyping method allows the comprehensive analysis of diverse mutations. We developed a genotyping method with an on-target site analysis software named Determine Allele mutations and Judge Intended genotype by Nanopore sequencer (DAJIN) that can automatically identify and classify diverse mutations, including point mutations, deletions, inversions, and knock-in. Our genotyping method with DAJIN can handle approximately 100 samples within a day and may become a new standard for validating genome editing outcomes.

QAlign: aligning nanopore reads accurately using current-level modeling

Motivation Efficient and accurate alignment of DNA/RNA sequence reads to each other or to a reference genome/transcriptome is an important problem in genomic analysis. Nanopore sequencing has emerged as a major sequencing technology and many long-read aligners have been designed for aligning nanopore reads. However, the high error rate makes accurate and efficient alignment difficult. Utilizing the noise and error characteristics inherent in the sequencing process properly can play a vital role in constructing a robust aligner. In this article, we design QAlign, a pre-processor that can be used with any long-read aligner for aligning long reads to a genome/transcriptome or to other long reads. The key idea in QAlign is to convert the nucleotide reads into discretized current levels that capture the error modes of the nanopore sequencer before running it through a sequence aligner. Results We show that QAlign is able to improve alignment rates from around 80% up to 90% with nanopore reads when aligning to the genome. We also show that QAlign improves the average overlap quality by 9.2, 2.5 and 10.8% in three real datasets for read-to-read alignment. Read-to-transcriptome alignment rates are improved from 51.6% to 75.4% and 82.6% to 90% in two real datasets. Availability and implementation https://github.com/joshidhaivat/QAlign.git. Supplementary information Supplementary data are available at Bioinformatics online.

Rapid genomic characterization of SARS-CoV-2 viruses from clinical specimens using nanopore sequencing

The novel SARS-CoV-2 outbreak has swiftly spread worldwide. The rapid genome sequencing of SARS-CoV-2 strains has become a helpful tool for better understanding the genomic characteristics and origin of the virus. To obtain virus whole-genome sequences directly from clinical specimens, we performed nanopore sequencing using a modified ARTIC protocol in a portable nanopore sequencer and validated a routine 8-h workflow and a 5-h rapid pipeline. We conducted some optimization to improve the genome sequencing workflow. The sensitivity of the workflow was also tested by serially diluting RNA from clinical samples. The optimized pipeline was finally applied to obtain the whole genomes of 29 clinical specimens collected in Hangzhou from January to March 2020. In the 29 obtained complete genomes of SARS-CoV-2, 33 variations were identified and analyzed. The genomic variations and phylogenetic analysis hinted at multiple sources and different transmission patterns during the COVID-19 epidemic in Hangzhou, China. In conclusion, the genomic characteristics and origin of the virus can be quickly determined by nanopore sequencing following our workflows.

F5N : Nanopore Sequence Analysis Toolkit for Android Smartphones

F5N is the first ever Android application for nanopore sequence analysis on a mobile phone, comprised of popular tools for read alignment (Minimap2), sequence data manipulation (Samtools) and methylation calling (F5C/Nanopolish). On NA12878 nanopore data, F5N can perform a complete methylation calling pipeline on a mobile phone in ∼15 minutes for a batch of 4000 nanopore reads (∼34 megabases). F5N is not only a toolkit but also a framework for integrating existing C/C++ based command line tools to run on Android. F5N will enable performing nanopore sequence analysis on-site when used with an ultra-portable nanopore sequencer (eg: MinION or the anticipated smidgION), consequently reducing the cost for special computers and high-speed Internet.Availability and implementationF5N Android application is available on Google Play store at https://play.google.com/store/apps/details?id=com.mobilegenomics.genopo&hl=en and the source code is available on Github at https://github.com/SanojPunchihewa/[email protected]