id	author	title	date	pages	extension	mime	words	sentences	flesch	summary	cache	txt
cord-327808-k3jec87p	Zhu, Yunkai	The S1/S2 boundary of SARS-CoV-2 spike protein modulates cell entry pathways and transmission	2020-08-25		.txt	text/plain	2754	155	61	We found that the virus with intact spike (Sfull) preferentially enters cells via fusion at the plasma membrane, whereas a clone (Sdel) with deletion disrupting the multi-basic S1/S2 site instead utilizes a less efficient endosomal entry pathway. The sequence at the S1/S2 boundary contains a cleavage site for the furin protease, 61 which could preactivate the S protein for membrane fusion and potentially reduce the 62 dependence of SARS-CoV-2 on plasma membrane proteases, such as transmembrane 63 serine protease 2 (TMPRSS2), to enable efficient cell entry (Shang et al., 2020) . Intriguingly, 188 these genes edited also significantly inhibited the infection by pseudovirus bearing the 189 spike protein of MERS-CoV in A549-ACE2-DPP4 cells ( Figure 3D ). Although no infectious virus was detected by focus-forming 299 assay (data not shown), viral RNA levels were higher in fecal samples for Sfull (20 and 300 40-fold) than Sdel at days 2 and 4, respectively ( Figure 5B ).	./cache/cord-327808-k3jec87p.txt	./txt/cord-327808-k3jec87p.txt