The reasons of Trithorax-like expression disturbance in Trl (3609) allele of Drosophila melanogaster.

The regulatory region of the Trl gene was analyzed using the mutation Trl (3609) , resulting from the insertion of the P-element into the promoter region of the gene as well as mutations obtained on its basis. It is shown that two last transcription start sites, which are most often used in vitro in S2 cells, are almost not used in vivo. Experimental data indicate that transcription terminators in transposons play an important role in the decrease in the transcription level of the recipient gene.