POLY(A) SHORTENING OF COREGULATED TRANSCRIPTS IN DROSOPHILA

The 71E ecdysterone-regulated puff of Drosophila melanogaster contains a cluster of six coregulated "late" genes which are expressed in the prepupal salivary gland. The resulting transcripts exhibit a decrease in their length during the 12-hr period in which they accumulate. Using the enzyme ribonuclease H, we show that this size decrease is a result of a progressively shorter poly(A) tract and suggest that these transcripts undergo an active sequential shortening of their poly(A) tracts in prepupal salivary glands. It is interesting to note that this shortening precedes the complete loss of these transcripts from the RNA population.