Total RNA extraction using the RNeasy Plus Mini Kit (Qiagen, Venlo, Netherlands). Total RNA was eluted in 10 μl of RNase-free water. For RNA-Seq, cDNA was synthesized using a SMART-Seq mRNA LP (Takara Bio, San Jose, CA, USA) according to the manufacturer's protocol. The cDNA was then amplified for 15 PCR cycles, purified by AmPure XP magnetic beads (Beckman Coulter Genomics), and eluted with 15 μl of Elution Buffer. The purified cDNA was quantified fluorometrically using a Qubit 2.0 Fluorometer. Library size distribution was determined using the Agilent 2100 bioanalyzer using High-Sensitive DNA kit (Agilent Genomics). The SMART-Seq Library Prep Kit (Takara) was used to generate the libraries, with an input of 1 ng of cDNA. Libraries were pooled and sequenced to obtain 75-base-pair paired-end reads on the Illumina NextSeq550 platform to a depth of >20 million reads per sample.