id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-345651-admlzeu4	Wang, Gang	The N-Terminal Domain of Spike Protein Is Not the Enteric Tropism Determinant for Transmissible Gastroenteritis Virus in Piglets	2019-03-30		.txt	text/plain	6220	265	49	Using a novel approach, the clustered regularly interspaced short palindromic repeat (CRISPR)/CRISPR-associated protein 9 (Cas9) systems efficiently and rapidly rescued another recombinant virus with a 224-amino-acid deletion in the N-terminal domain of the TGEV Spike gene (S_NTD224), which is analogous to the N-terminal domain of porcine respiratory coronavirus. Homologous recombination was then performed using the ClonExpress II One Step Cloning Kit (Vazyme, Nanjing, Jiangsu, China) according to the manufacturer's instructions using 200 ng of recycled linearized pTGEV-GFP BAC, 45 ng of PCR products of S_NTD and two pairs of primers (rec-672SF/δS-NTDR and rec-672SR/δS-NTDF) ( Table 2) . To construct an infectious clone of TGEV, six overlapping cDNA fragments designated A to F were generated by reverse transcriptase PCR (RT-PCR) using total RNA extracted from PK-15 cells infected with TGEV WH-1 ( Figure 1A ,B). Complete genomic sequences, a key residue in the spike protein and deletions in nonstructural protein 3b of US strains of the virulent and attenuated coronaviruses, transmissible gastroenteritis virus and porcine respiratory coronavirus	./cache/cord-345651-admlzeu4.txt	./txt/cord-345651-admlzeu4.txt