Fig 1. A new mutant of vps24, vps24¹.

(A-C) The vps24 mutant exhibits locomotor and lifespan deficits. (A) vps24¹ /Df(3R)Exel6140 flies (vps24¹ /Df) exhibited rapid temperature sensitive (TS) paralysis at 38°C, whereas wild-type flies (WT) did not. Tests were truncated at 5 min if 50% TS paralysis had not occurred. (B) Climbing tests, carried out at a room temperature (RT) of 22–24°C, indicated no detectable climbing ability in the vps24 mutant. The climbing tests were truncated at 2 min if 50% climbing had not occurred and zero was given for the climbing index (see Materials and Methods). (C) Loss of the VPS24 function reduced lifespan with respect to WT. 7d old female flies raised at 20°C were examined in these and the following behavioral studies. Here and in subsequent figures, data points represent the mean ± SEM and asterisks mark significant differences from control values (P = 0.05). (D, E) vps24¹ mutation. (D) In vps24¹, an 11 bp deletion occurs at the beginning of the 1st intron and removes its splice donor signal. This disrupts splicing of the 1st intron in two ways: complete failure of splicing to remove the first intron (unspliced) or use of a cryptic splice donor site contained within the WT Exon 1 (see text). The broken line above the vps24¹ (unspliced) sequence represents continuation of Exon 1. (E) Each type of aberrant vps24 transcript (unspliced or cryptically spliced) encodes a drastically truncated polypeptide composed of the first 15 or 9 amino acids of VPS24 (full length is 223) followed by several amino acids of non-VPS24 protein sequence (in red). *, stop codon.