THE BASIS FOR GERMLINE SPECIFICITY OF THE HOBO TRANSPOSABLE ELEMENT IN DROSOPHILA-MELANOGASTER

Previous results suggested that the hobo transposable element is activ e predominantly in the germline of Drosophila. We investigate germline restriction ofhobo transposition by testing in vitro modified element s for their ability tomobilize marked elements in vivo. Although intac t hobo elements are germline specific, an hsp70 promoter - hobo transp osase fusion is active in the soma. Analysis of the hsp70-promoted tra nscript does not provide evidence for splicing. Moreover, the hobo pro moter confers germline bias to a highly sensitive reporter, Delta 2-3 P transposase. These results indicate that hobo transpositionis germli ne specific due to regulation of transposase production at the levelof transcription. Thus, although hobo is similar to the P transposable e lement in organization and tissue specificity, it differs in the under lying mechanism governing germline specific activity.