LIN28 protein is stage-specifically expressed in embryonic muscle, neurons, and epithelia, as well as in embryonic carcinoma cells; however, it is suppressed in most adult tissues except for skeletal and cardiac muscle.LIN28 mRNA is a target of the micro RNAs miR-125b and miRNA-125a.When the miREs were deleted, miRNA control over LIN28 nearly vanished. Lin28 downregulation by miR-125 involved reductions in both translational efficiency and mRNA abundance.An important target of Lin28 is Igf2, a growth and differentiation factor for muscle tissue. Interaction of Lin28 with translation initiation complexes in skeletal myoblasts and in the embryonic carcinoma cell line P19 was confirmed by localization of Lin28 to the stress granules, temporary structures that contain stalled mRNA-protein translation complexes.