High frequency retrotransposition in cultured mammalian cells.
We previously isolated two human L1 elements (L1.2 and LRE2) as the progenitors of disease-producing insertions. Here, we show these elements can actively retrotranspose in cultured mammalian cells. When stably expressed from an episome in HeLa cells, both elements retrotransposed into a variety of chromosomal locations at a high frequency. The retrotransposed products resembled endogenous L1 insertions, since they were variably 5' truncated, ended in poly(A) tracts, and were flanked by target-site duplications or short deletions. Point mutations in conserved domains of the L1.2-encoded proteins reduced retrotransposition by 100- to 1000-fold. Remarkably, L1.2 also retrotransposed in a mouse cell line, suggesting a potential role for L1-based vectors in random insertional mutagenesis.
Moran
J V
JV
Department of Genetics, University of Pennsylvania School of Medicine, Philadelphia 19104, USA.
Holmes
S E
SE
Naas
T P
TP
DeBerardinis
R J
RJ
Boeke
J D
JD
Kazazian
H H
HH
D000818:Animals; D001483:Base Sequence; D002875:Chromosomes / Q000235:genetics; D017124:Conserved Sequence; D003545:Cysteine / Q000235:genetics; D004252:DNA Mutational Analysis; D005347:Fibroblasts / Q000502:physiology; D016678:Genome; D006367:HeLa Cells / Q000502:physiology; D006801:Humans; D008322:Mammals; D051379:Mice; D016296:Mutagenesis / Q000235:genetics; D016366:Open Reading Frames / Q000235:genetics; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D018626:Retroelements / Q000235:genetics*; D013997:Time Factors
D012333:RNA, Messenger; D018626:Retroelements; D003545:Cysteine