Two subfamilies of murine retrotransposon ETn sequences.
Early transposon (ETn) elements are 5.7-kb retrotransposons found in the murine genome. We have sequenced large portions of two ETn elements that have apparently transposed within the DNA of a murine myeloma cell line, P3.26Bu4. One of the transposed ETn elements has 5' and 3' long terminal repeats (LTRs) that are exact duplicates of each other and has a 6-bp target site duplication. These results suggest that this element, which inserted into an immunoglobulin gamma 1 switch region, moved by a retrotransposition process. Our nucleotide sequences confirm that individual ETn elements are very similar to one another and lack open reading frames. However, the ETn sequences reported here and those previously described differ significantly near their 5' LTRs, including 200 bp of weak similarity and 240 bp of complete disparity. Southern hybridization analysis suggests that both subfamilies of ETn sequences are represented many times in the mouse genome. The possibility that the disparate sequences have a role in transposition by ETn elements is discussed.
Shell
B E
BE
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109-0620.
Collins
J T
JT
Elenich
L A
LA
Szurek
P F
PF
Dunnick
W A
WA
D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D003001:Cloning, Molecular / Q000379:methods; D004247:DNA / Q000235:genetics; D015342:DNA Probes; D004251:DNA Transposable Elements; D007143:Immunoglobulin Heavy Chains / Q000235:genetics; D051379:Mice; D008807:Mice, Inbred BALB C; D008969:Molecular Sequence Data; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid
D015342:DNA Probes; D004251:DNA Transposable Elements; D007143:Immunoglobulin Heavy Chains; D004247:DNA