Correction to: Nature Biotechnology https://doi.org/10.1038/s41587-021-00842-6, published online 11 March 2021.

In the version of this article initially published online, an additional PCR step was missing at the beginning of the last paragraph in the “Nanopore library preparation” section of the Methods: To obtain sufficient cDNA products for sequencing, PCR amplification was performed using 2 μL of cDNA with NEBNext LongAmp Taq DNA Polymerase and SMARTer primers under the following conditions: 95 °C for 30 s; 19 or 20 cycles of 95 °C for 15 s, 62 °C for 15 s, and 65 °C for 120 s; 65 °C for 6 min and hold at 4 °C. Also, the following has been added at the end of this section: Steps for library construction are detailed in the CIRI-long manual pages at https://ciri-cookbook.readthedocs.io/en/latest/CIRI-long_sequencing.html. The error has been corrected in the print, PDF and HTML versions of the article.