Isoseq of fibroblast
We purified polyA RNA using oligo-dT magnetic beads (Dynal: Thermo Fisher Scientific Inc.). Double-stranded cDNA with 96 random barcodes was prepared, amplified and subjected to hybridization capture followed the protocols detailed in (Dougherty et al. 2018). Hybridization probes were designed to target the duplicated exons of TCAF2. Following post-capture PCR, the amplified dsDNA was purified on magnetic beads (AMPure PB; PacBio) and then subjected to library preparation for long-read sequencing (SMRTbell Template Prep Kit 1.0; PacBio with barcoded SMRTbell adapters). SMRT sequencing was performed on the Sequel platform with Sequel v3.0 chemistry (PacBio) with LR SMRT Cells with 2-hour pre-extension and 20-hour movies. Reads corresponding to each sample were extracted by their SMRTbell barcodes and circular consensus sequences were generated from the raw subreads using SMRT Link with minimum number of pass set to 1. The program lima in the Iso-Seq3 pipeline (https://github.com/PacificBiosciences/IsoSeq3) was applied to remove the 5' and 3' dual barcodes and also obtain the unclustered FLNC reads. Parameters used were: lima --isoseq --dump-clips.