Presence of genomic polyadenylate and absence of detectable virion transcriptase in human coronavirus OC-43

Human coronavirus RNA, prepared by extraction of purified virions with phenol-chloroform, consists of a major 15 to 55S class and a minor 4S class of RNA fragments. Polyadenylic acid [poly (A)] sequences are present in 15 to 55S but not in 4S RNA, suggesting different functions for each class. A stretch of poly (A) of approximately 19 adenosine monophosphate residues was obtained in sizing experiments after digesting OC-43 RNA with pancreatic and T1 ribonucleases. An OC-43 virion RNA transcriptase could not be detected with systems optimal for detecting the transcriptases of influenza and Newcastle disease virus.