Hypothetical Models of CRK10 Regulation by Cytokinin. Pre-mRNA and mRNA are depicted by wavy black arrows with a red segment indicating intron 1, or a gap indicating removal of intron 1. Blue arrows indicate the flow of information. Positions of capping or cleavage and polyadenylation are shown as GpppG and A(n), respectively. Parallel lines represent the plasma membrane (PM) with the cell exterior at the bottom.