FIG. 4.

TART A- and B-subfamily elements yield full-length transcripts of several sizes. An autoradiograph of a Northern blot of total RNA from adult 2057 flies probed with TART sequences is shown. In this stock ORF probes detect two bands of sense-strand RNA migrating above the 9.5-kb marker. (Both ORF1 and ORF2 probes give this result; ORF2 is shown.) The A-subfamily 3′ UTR probe identifies the top band as TART A RNA, while the B-subfamily 3′ UTR probe labels a band corunning with the lower band but seen only in RNA from males (indicated by the arrow in the B 3′ UTR lane). Because females in this stock lack full-length B elements, we conclude that the band just above 9.5 kb hybridizing with ORF probes in females represents a third subfamily of TART found both in males and females. This third-subfamily RNA comigrates with the B transcript in males. Both 3′ UTR probes detect very abundant short sense RNAs (<2 kb). Probes for antisense ORF sequences detect two transcripts whose gel mobilities differ slightly from that of the large sense RNAs. The larger antisense transcript may comigrate with the smaller sense RNA. Both of the large antisense RNAs hybridize with A-subfamily 3′ UTR probes. The B-subfamily 3′ UTR detects a smaller and less abundant antisense RNA seen only in males with either ORF or B 3′ UTR probes (indicated by the arrow in the B 3′ UTR lane). The label at ∼2 kb is due to RNA trapped by rRNA.