Total RNA was harvested using Qiazol (Qiagen), purified from DNA contamination through DNase I (Qiagen) and enriched by  RNeasy (Qiagen) columns for gene expression profiling. Quantity and integrity of the extracted RNA were assessed by NanoDrop Spectrophotometer (NanoDrop Technologies, DE) and by Agilent 2100 Bioanalyzer (Agilent Technologies, CA), respectively. To investigate chromatin accessibility dynamics, the ATAC-seq protocol developed by Buenrostro et al. was used, with minor modifications