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Jaki, L.

Publications and source records attributed to Jaki, L..

2 recordsLinked to original sources

varVAMP: automated pan-specific primer design for tiled full genome sequencing and qPCR of highly diverse viral pathogens.

Time- and cost-saving surveillance of viral pathogens is achieved by tiled sequencing in which a viral genome is amplified in overlapping PCR amplicons and qPCR. However, designing pan-specific primers for viral pathogens that have high genomic variability represents a major challenge. Here, we present a bioinformatics command-line tool, called varVAMP (variable virus amplicons). It relies on multiple sequence alignments of highly variable virus sequences and enables automatic pan-specific primer design for qPCR or tiled amplicon whole genome sequencing. The varVAMP software guarantees pan-specificity by two means: it designs primers in regions with minimal variability and introduces degenerate nucleotides into primer sequences to compensate for common sequence variations. We demonstrate varVAMPs utility by designing and evaluating novel pan-specific primer schemes suitable for sequencing the genomes of SARS-CoV-2, Hepatitis E virus, rat Hepatitis E virus, Hepatitis A virus, Borna-disease-virus-1, and Poliovirus. Moreover, we established highly sensitive and specific Poliovirus qPCR assays that could potentially simplify current Poliovirus surveillance. Importantly, wet-lab and bioinformatic techniques established for SARS-CoV-2 tiled amplicon sequencing were readily transferable to these new primer schemes and will allow sequencing laboratories to extend their established methodology to other human pathogens.

bioinformatics↗

Combining CRISPR/Cas mediated terminal resolution with a novel genetic workflow to achieve high diversity adenoviral libraries

While recombinant Adenoviruses (rAds) are widely used in both laboratory and medical gene transfer, library-based applications using this vector platform are not readily available. Recently, we developed a new method, the CRISPR/Cas9 mediated in vivo terminal resolution (CTR) aiding high efficiency rescue of rAds from recombinant DNA. Here we report on a genetic workflow that allows construction of BAC-based rAd-libraries employing the efficiency of CTR. We utilized frequent, pre-existing genomic sequences to allow insertion of a selection marker, complementing two selected target sites into novel endonuclease recognition sites. In a second step, this selection marker is replaced with a transgene or mutation of interest via Gibson assembly. Our approach does not cause unwanted genomic off-target mutations while providing substantial flexibility for the site and nature of the genetic modification. This new genetic workflow, which we termed half-site directed fragment replacement (HFR) allows introduction of >106 unique modifications into rAd encoding BACs using laboratory scale methodology. To demonstrate the power of HFR, we rescued barcoded viral vector libraries yielding a diversity of [~]2.5x104 modified rAd per cm2 of transfected cell culture. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=141 SRC="FIGDIR/small/566979v1_ufig1.gif" ALT="Figure 1"> View larger version (31K): org.highwire.dtl.DTLVardef@1db61a7org.highwire.dtl.DTLVardef@1e85764org.highwire.dtl.DTLVardef@c17178org.highwire.dtl.DTLVardef@a299_HPS_FORMAT_FIGEXP M_FIG C_FIG

synthetic biology↗