gga‑microRNA‑375 negatively regulates the cell cycle and proliferation by targeting Yes‑associated protein 1 in DF‑1 cells

MicroRNAs (miRNAs/miRs) serve a key role in regulating the cell cycle and inducing tumorigenesis. Subgroup J of the avian leukosis virus (ALV‑J) belongs to the family Retroviridae, subfamily Orthoretrovirinae and genus Alpharetrovirus that causes tumors in susceptible chickens. gga‑miR‑375 is downregulated and Yes‑associated protein 1 (YAP1) is upregulated in ALV‑J‑induced tumors in the livers of chickens, and it has been further identified that YAP1 is the direct target gene of gga‑miR‑375. In the present study, it was found that ALV‑J infection promoted the cell cycle and proliferation in DF‑1 cells. As the cell cycle and cell proliferation are closely associated with tumorigenesis, further experiments were performed to determine whether gga‑miR‑375 and YAP1 were involved in these cellular processes. It was demonstrated that gga‑miR‑375 significantly inhibited the cell cycle by inhibiting G1 to S/G2 stage transition and decreasing cell proliferation, while YAP1 significantly promoted the cell cycle and proliferation. Furthermore, these cellular processes in DF‑1 cells were affected by gga‑miR‑375 through the targeting of YAP1. Collectively, the present results suggested that gga‑miR‑375, downregulated by ALV‑J infection, negatively regulated the cell cycle and proliferation via the targeting of YAP1.