The G1 checkpoint, also known as the restriction point in mammalian cells and the start point in yeast, is the point at which the cell becomes committed to entering the cell cycle. As the cell progresses through G1, depending on internal and external conditions, it can either delay G1, enter a quiescent state known as G0, or proceed past the restriction point. DNA damage is the main indication for a cell to "restrict" and not enter the cell cycle. The decision to commit to a new round of cell division occurs when the cell activates cyclin-CDK-dependent transcription which promotes entry into S phase. This check point ensures the further process.