A HOTSPOT FOR THE DROSOPHILA GYPSY RETROELEMENT IN THE OVO LOCUS

The Drosophila retroelement gypsy has a number of unusual features inc luding an,unusual LTR terminal sequence and an apparent target sequenc e preference. The ovo locus is a known hotspot for gypsy insertion. We examined the target sequence preference of gypsy within ovo by isolat ing 26 new insertions and sequencing the gypsy/ovo junctions. Insertio ns were found at multiple sites within the ovo locus. The insertions c lustered within an similar to 150 bp region in the non-translated regi on of the ovo beta transcript, with most insertions falling within the first intron, There were seven sites of insertion within this region and these mostly conform to the consensus sequence YRYRYR (where Y = p yrimidine and R = purine). However,this target sequence is at best nec essary but not sufficient to specify a hotspot, as there were several other sequences conforming to this consensus in the ovo locus that wer e not hit. The results indicate that gypsy may have a higher degree of target specificity than most infectious LTR retroelements.