Fig. 6. sal mutants exhibit defects in the a2 cuticle and in the a2-a3 joint necessary for audition. (A) salFCK–25/Df(2L)32FP-5 FRT40A antenna. a2 is reduced in size distally (arrowheads), exposing the stalk (arrow) of a3 that inserts into a2. (B) Optical section of the interior of a wild-type a2. The circular outline of the a2/a3 joint to which the chordotonal organs of the JO attach is indicated (arrowhead). (C) Optical section of the interior of an a2 in which a sal/salr null clone has been induced, and the circular outline of the a2/a3 joint is disrupted (arrowhead). (D) Wild-type expression of Sal (red) and Ato (green) in the eye-antennal disc. (E) Expression of Sal (red) and Ato (green) in a salFCK–25/Df(2L)32FP-5 FRT40A antenna disc. Sal is lacking in the antenna disc, but Ato is still expressed. Note that Sal is expressed normally in the eye disc of this allelic combination. (F) Expression of Sal (red) in an ato1 eye-antennal disc. Sal is lost from the eye disc, but expressed normally in the antenna. (G) Sal (red) and Dac (blue) expression in a ss null (Df(3R)ssD114.4/ssD114.9) eye-antennal disc. Both are expressed normally.
