The RACE protocol was performed as described (45 (link)). Briefly, total RNA was extracted using TRIzol (Ambion), followed by ligation of 5′-adenylated-3′-blocked adapter (New England Biolabs) using T4 RNA ligase truncated KQ (New England Biolabs). Ligated RNAs were purified and cDNAs were synthesized using SuperScript III Reverse Transcriptase (Thermo Fisher Scientific). PCR amplification was performed using gene specific primers and PCR amplicons were resolved on 2.5% agarose gels to visualize mature and extended transcripts. Primers used are given in Supplementary Table S1.