Gaur, P. | Search bioRxiv

bioRxiv2018

Rapid preimplantation genetic screening (PGS) using a handheld, nanopore-based, DNA sequencer

ObjectiveTo determine if a handheld, nanopore-based DNA sequencer can be used for rapid preimplantation genetic screening (PGS).\n\nDesignRetrospective study.\n\nSettingAcademic medical center.\n\nPatient(s)Amplified genomic DNA from euploid and aneuploid trophectoderm biopsy samples (n=9) that was also tested using traditional next generation sequencing (NGS).\n\nIntervention(s)Short-read DNA library preparation and nanopore-based sequencing using a hand-held MinION sequencer.\n\nMain outcome measure(s)Comparison of cytogenetic testing result from NGS and nanopore-based sequencing and the time required for library preparation and sequencing.\n\nResult(s)Multiplexed short-read DNA library preparation was completed in 45 minutes. Sequencing times varied from 1 to 2 hours. These times compare favorably with NGS library preparation (>3.5 hours) and sequencing (>12 hours) times. Whole-chromosome aneuploidy screening results obtained from nanopore-based sequencing were identical to those obtained using NGS.\n\nConclusion(s)Methods for PGS of embryos have evolved from FISH to microarrays and most recently to NGS. Here we report the first application of nanopore-based sequencing for PGS on trophecoderm biopsy samples using a rapid multiplex short-read nanopore sequencing library preparation. Aneuploidy screening could be performed on 5 samples in one nanopore flowcell with 1 to 2 hour sequencing times. Overall, nanopore sequencing is a promising tool to perform rapid PGS assay onsite with a rapid turnover time, enabling same day testing and embryo transfer thus obviating the need for complex, large and expensive DNA sequencers or frozen embryos.

genetics↗

bioRxiv2017

The immunomodulatory CEA cell adhesion molecule 6 (CEACAM6/CD66c) is a candidate receptor for the influenza A virus

To establish a productive infection in host cells, viruses often use one or multiple host membrane glycoprotein as their receptors. For Influenza A virus (IAV) such a glycoprotein receptor has not been described, to date. Here we show that IAV is using the host membrane glycoprotein CD66c as a receptor for entry into human epithelial lung cells. Neuraminidase (NA), a viral spike protein binds to CD66c on the cell surface during IAV entry into the host cells. Lung cells overexpressing CD66c showed an increase in virus binding and subsequent entry into the cell. Upon comparison, CD66c demonstrated higher binding capacity than other membrane glycoproteins (EGFR and DC-SIGN) reported earlier to facilitate IAV entry into host cells. siRNA mediated knockdown of CD66c from lung cells inhibited virus binding on cell surface and entry into cells. Blocking CD66c by antibody on the cell surface resulted in decreased virus entry. We found CD66c is a specific glycoprotein receptor for influenza A virus that did not affect entry of non-IAV RNA virus (Hepatitis C virus). Finally, IAV pre-incubated with recombinant CD66c protein when administered intranasally in mice showed decreased cytopathic effects in mice lungs. This publication is the first to report CD66c (CEACAM6) as a glycoprotein receptor for Influenza A virus.\n\nSignificance StatementCells are enclosed by a semipermeable membrane that allows selective exchange of biomolecules between cells and their surroundings. A set of specialized proteins in this semipermeable membrane, work like gatekeepers to the cell and regulate entry of these biomolecules. One class of such surface proteins is termed as receptors. Viruses bind to one or more of these receptors and manipulate gatekeepers for their own successful entry into host-cells. A membrane protein that influenza A virus (Flu virus) uses for entry into the cells was not discovered till date. This study reports for the first time, a receptor for influenza A virus, that was sought after by researchers for decades. The viral receptor is a promising target that can be used to inhibit virus entry into host cells.

microbiology↗