MicroRNA-101 (miR-101) is frequently downregulated in various cancers.To date,the regulatory networks of miR-101 remain obscure.In this study,we demonstrated that miR-101 was mainly transcribed from human miR-101-2 and mouse miR-101b gene loci.Subsequent analyses revealed that activator protein-1 (AP-1) directly binded to the-17.4 to16.4k region upstream of pre-miR-101-2 and activated the expression of miR-101.On the other hand,miR-101 could inhibit the expression of ERK2 and c-Fos,two key factors of the AP-1 pathway,by binding to their 3-UTRs.