Human LIN-28A is a 30 kDa (209 amino acids) cytoplasmic RNA-binding protein with an N-terminal cold shock domain and two C-terminal CCHC zinc finger domains. It is expressed by various undifferentiated embryonic cell types and is also present in adult cardiac and skeletal muscle. Expression of LIN-28A has been shown to be regulated by micro-RNA. Human LIN-28A shares 98% and 97% amino acid sequence homology with rat and mouse LIN-28A, respectively.