2 TIGHTLY-LINKED DROSOPHILA MALE ACCESSORY-GLAND TRANSCRIPTS WITH THESAME DEVELOPMENTAL EXPRESSION DERIVE FROM INDEPENDENT TRANSCRIPTION UNITS

Acp26Aa and Acp26Ab are Drosophila male accessory gland transcripts th at are tightly linked and transcribed from the same DNA strand. Despit e their being separated by 20 base pairs, the transcripts show identic al responses to several developmental signals. These observations make it important to determine whether the 26A region contains two separab le genes with the same developmental expression or a single developmen tally regulated transcription unit whose product is processed to yield Acp26Aa and Acp26Ab. We show that Acp26Aa and Acp26Ab are separate mR NAs using a reverse transcription-polymerase chain reaction assay and reporter gene fusions. We also show that the regulatory elements for A cp26Ab lie within a fragment containing the intergenic region and tran scribed sequences of Acp26Aa and Acp26Ab.