Abstract
The BMC1 element has been found in the Bombyx mori genome as an interspersed repetitious sequence classified as a non-LTR retrotransposon similar to the Ll family in mammals. The BMC1 family has a highly conserved structure ; however, many copies contain defects in their reverse transcriptase domains and 5′-truncations. Duplication of target sequences at the 5′ and 3′ ends of the elements generated by transposition events are readily detected. To attempt gene introduction into the silkworm, B. mori, genome, we used the BMC1 element as a candidate for a transformation vector. A plasmid construct with the element and a cat gene for a reporter was transfected into cultured cells. In the bulk DNA isolated from cells transfected with the plasmid containing or lacking the BMC1 sequence shifted bands were observed only if BMC1 was present. One of five clones isolated from transfected lines has evidence for recombination to B, mori genomic BMC1 sequences. This indicates that this element might be useful for constructing a transformation vector into the B. mori genome.
