Activity analysis and preliminary inducer screening of the chicken DAZL gene promoter

This study was aimed at identifying the active control area of chicken DAZL gene core promoter, to screen optimum inducers of the DAZL gene, thus to enhance the differentiation of embryonic stem cells into spermatogonial stem cells. Fragments of chicken DAZL gene promoter were cloned into fluorescent reporter plasmids and transfected into DF-1 cells. Then Dual-Luciferase® Reporter Assay System was used to identify the activity of the DAZL gene under different inducers. Our studies showed that the DAZL core promoter region for the Suqin yellow chicken was -383 to -39 bp. The dual-luciferase® reporter showed that all-trans retinoic acid (ATRA), a retinoic acid receptor alpha agonist (tamibarotene/Am80), or estradiol (E2) could significantly enhance DAZL transcription. The in vitro inductive culture of chicken ESCs demonstrated that, with ATRA treatment, DAZL transcription peaked at 6 days and then decreased slowly; whereas, DAZL transcription was continuous and peaked at 10 days with Am80 treatment. E2 treatment significantly increased DAZL expression after 8 days. All three treatments were associated with the appearance of male germ cell (MGC)-like cells on day 10. These results provide the optimum inducer screening of the DAZL gene and lay the foundation for further screening of compounds that can induce the differentiation of ESCs into MGCs in vitro.