ZFIN Image: Mathavarajah et al., 2023, Fig. 7

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Figure Caption

Fig. 7

Overview of the suppression of LINE-1 retrotransposition in jawed vertebrates through the collective functions of PML, Plex9 and TREX1 enzymes. In fish, PML and novel Plex9 enzymes play a major role in suppressing both LINE-1 and LINE-2 elements. Despite the loss of PML in Teleost fish genomes, they have retained Plex9 genes for the purpose of restricting LINE retrotransposition. TREX1 appears later in tetrapods, where Plex9 genes are lost. In addition, enzymatic PML function is lost and the protein forms nuclear bodies rather than localizing to the cytoplasm. However, PML has a retained an exonuclease-independent role for the surveillance of LINEs by shuttling to the cytoplasm to suppress the LINE1 retrotransposition. Thus, the three protein families (PML, Plex9 and TREX) share an important function in maintaining genome integrity in jawed vertebrates by repressing LINE-1 propagation.

Acknowledgments

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