The ORF1 Protein Encoded by LINE-1: Structure and Function During L1 Retrotransposition

[摘要] LINE-1 or L1 is an autonomous non-LTR retrotransposon in mammals.Retrotransposition requires the function of the twoL1-encoded polypeptides, ORF1p and ORF2p. Early recognition ofregions of homology between the predicted amino acid sequence ofORF2 and known endonuclease and reverse transcriptase enzymes ledto testable hypotheses regarding the function of ORF2p inretrotransposition. As predicted, ORF2p has been demonstrated tohave both endonuclease and reverse transcriptase activities. Incontrast, no homologs of known function have contributed to ourunderstanding of the function of ORF1p during retrotransposition.Nevertheless, significant advances have been made such that we nowknow that ORF1p is a high-affinity RNA-binding protein that formsa ribonucleoprotein particle together with L1 RNA. Furthermore,ORF1p is a nucleic acid chaperone and this nucleic acid chaperoneactivity is required for L1 retrotransposition.

[学科分类] 基础医学