Together, a low basal, though similar level of de novo synthesized nucleocapsid-specific sgRNA in ACE2-KO-H1299 and parental cells upon infection with SARS-CoV-2 isolates and chimeric spike viruses suggests that NCI-H1299 cells provide other receptors than ACE2, whose usage nevertheless results in an abortive infection. Here, ACE2 is linked to infection.