RNA from cells were extracted by Trizol (invitrogen, 15596018), then precipitated by isopropanol; genomic DNA were extrated by phenol chloroform extraction and precipitated by ethanol. Libraries of genomic DNA were construted by using NEBNext Ultra DNA Library Prep Kit for Illumina (NEB #7370L); Libraries of polyA RNA were constructed by using NEBNext poly(A) RNAseq library preparation kits (EE6100L).