PTBP1 and COVID-19: The ODF3B (ciliary microtubule associated protein 1B)–SCO2 (synthesis of cytochrome c oxidase 2) (OS) and TYMP (thymidine phosphorylase)-SCO2 (TS) chimeric isoforms made up the majority of the 14 chimeras found only in the PTBP1 knockdown and COVID-19 samples (Fig. 6A).