Dm. Woodcock et al., A SENSITIVE RNASE PROTECTION ASSAY TO DETECT TRANSCRIPTS FROM POTENTIALLY FUNCTIONAL HUMAN ENDOGENOUS L1 RETROTRANSPOSONS, Biochemical and biophysical research communications, 222(2), 1996, pp. 460-465
A high background of read-through transcripts from degenerate human L1
retrotransposons is present in almost all human cell types. This prev
ents the detection of RNA transcripts from potentially functional elem
ents. To overcome this, we have developed an RNase protection assay ba
sed on the reconstructed consensus sequence for the 5' end of the majo
r L1 family. In the human Ntera2D1 teratocarcinoma cell line, this ass
ay readily detected L1 transcripts that were located primarily in the
cytoplasm and where 20% were in filterable particles. By this assay, p
otentially functional L1 elements are also transcriptionally active in
lymphocytes from some but not all normal individuals. Together with t
he full length protection product, there were three other discrete L1
RNAs, two of which (305 and 275 bases) were transcribed from the 5' en
d of the L1 element. These smaller L1 RNAs do not appear to be derived
from transcripts from divergent L1 families but are either discrete s
horter transcripts or specifically processed products from longer init
ial transcripts. (C) 1996 Academic Press, inc.