Biology subjects

Tabatabaei, S. K.

Publications and source records attributed to Tabatabaei, S. K..

3 recordsLinked to original sources

bioRxiv2023

One-pot Golden Gate Assembly of an avian infectious bronchitis virus reverse-genetics system

Avian infectious bronchitis is an acute respiratory disease of poultry of particular concern for global food security. Investigation of Infectious Bronchitis Virus (IBV), the causative agent of avian infectious bronchitis, via reverse genetics enables deeper understanding of virus biology and a rapid response to emerging variants. Classic methods of reverse genetics for IBV can be time consuming, rely on recombination for the introduction of mutations, and, depending on the system, can be subject to genome instability and unreliable success rates. In this study, we have applied data-optimized Golden Gate Assembly design to create a rapidly executable, flexible, and faithful reverse genetics system for IBV. The IBV genome was divided into 12 fragments at high-fidelity fusion site breakpoints. All fragments were synthetically produced and propagated in E. coli plasmids, amenable to standard molecular biology techniques for DNA manipulation. The assembly can be carried out in a single reaction, with the products used directly in subsequent viral rescue steps. We demonstrate the use of this system for generation of point mutants and gene replacements. This Golden Gate Assembly-based reverse genetics system will enable rapid response to emerging variants of IBV, particularly important to vaccine development for controlling spread within poultry populations.

genetics↗

bioRxiv2021

Expanding the Molecular Alphabet of DNA-Based Data Storage Systems with Neural Network Nanopore Readout Processing

DNA is a promising next-generation data storage medium, but the recording latency and synthesis cost of oligos using the four natural nucleotides remain high. Here, we describe an improved DNA-based storage system that uses an extended 11-letter molecular alphabet combining natural and chemically modified nucleotides. Our extended-alphabet molecular storage paradigm offers a nearly two-fold increase in storage density and potentially the same order of reduction in the recording time. Experimental results involving a library of 77 custom-designed hybrid sequences reveal that one can readily detect and discriminate different combinations and orders of monomers via MspA nanopores. Furthermore, a neural network architecture designed to classify raw current signals generated by Oxford Nanopore Technologies sequencing ensures an average accuracy exceeding 60%, which is 39 times higher than that of random guessing. Molecular dynamics simulations reveal that the majority of modified nucleotides do not induce dramatic disruption of the DNA double helix, making the extended alphabet system potentially compatible with PCR-based random access data retrieval. The methodologies proposed provide a forward path for new implementations of molecular recorders.

synthetic biology↗

bioRxiv2019

DNA Punch Cards: Encoding Data on Native DNA Sequences via Topological Modifications

Synthetic DNA-based data storage systems have received significant attention due to the promise of ultrahigh storage density and long-term stability. However, all platforms proposed so far suffer from high cost, read-write latency and error-rates that render them noncompetitive with modern optical and magnetic storage devices. One means to avoid synthesizing DNA and to reduce the system error-rates is to use readily available native DNA. As the symbol/nucleotide content of native DNA is fixed, one may adopt an alternative recording strategy that modifies the DNA topology to encode desired information. Here, we report the first macromolecular storage paradigm in which data is written in the form of "nicks (punches)" at predetermined positions on the sugar-phosphate backbone of native dsDNA. The platform accommodates parallel nicking on multiple "orthogonal" genomic DNA fragments and paired nicking and disassociation for creating "toehold" regions that enable single-bit random access and strand displacement in-memory computations. As a proof of concept, we used the programmable restriction enzyme Pyrococcus furiosus Argonaute to punch two files into the PCR products of Escherichia coli genomic DNA. The encoded data is accurately reconstructed through high-throughput sequencing and read alignment.

synthetic biology↗