Table 1.

Pathways used to manage epigenetic silencing and post-transcriptional components of LINE-1.

Pathway	Proteins	Compartment	Cell Type/Context	Description
RNase	RNase L, RNase H2, other cellular RNases	Cytoplasm, Nucleus	Demonstrated in human ovarian cancer cells, HeLa, HEK 293 T and SW982 cells	Cleavage of mRNAs from dsRNA [24] and RNA:DNA duplexes [25]
RNAi	Dicer, Exportin, RISC (contains Argonaute, others and siRNA)	Cytoplasm	All	Known to be generated by sense and antisense transcripts, as found in LINE-1. Plays a role in maintaining methylation H3k9me3 [29], [33], [41]
Granule Localization	MOV10, ZAP26, SAMHD1 [42]	Cytoplasm, stress granules and multi-vesicular bodies	All	General pathways involving localization of LINE-1 proteins, RNAs, and DNA in stress granules and multivesicular bodies [27]. Pathway involved in degradation, exosome formation and potentially processing bodies [42].
PIWI Interacting RNAs (piRNAs)	DNMT3L, PIWIL1, PIWIL2, PIWIL4 [22](aka murine MIWI2)	Nucleus, cytoplasm	Neoplasms, male germ line [13]. Demonstrated to play a role in HBEC LINE-1 propagation [37]	Leads to methylation of genomic LINE-1, members of the Argonaute family requires piRNA as a guide RNA.
apolipoprotein B mRNA editing enzyme [13]	APOBEC3A, APOBEC3B and APOBEC3C [42], [43], [44]	Nucleus	All, studies in HeLA	Inhibits reverse transcriptase (eg. Vif-deficient HIV-1 viruses are suppressed), Cytidine deaminase that converts dC to dU on forming DNA minus strands during reverse transcription.