Fig. 3. Alternative splicing of sma-9 transcripts. sma-9 cDNA clones reveal a complex alternative splicing at both 5' and 3' ends. At least three N terminus and seven C terminus forms were found. Predicted exons 4, 15 and 20 are labeled. Approximate locations of the termination codons in qc3 and wk55 are shown above the predicted exon structure. Gray boxes represent unique C-terminal sequences; an alternative exon 15 with two extra bases is indicated in yellow. cDNA clones representing each variant are: class A - pCS234 from RT-PCR; class B - yk1285a11; class C - pCS272 from RT-PCR; class Ia - yk128a8, yk1136g02 and yk1109f01; class Ib - yk43h3; class Ic - G-dvp11458.x (Walhout et al., 2000); class IIa - yk6d10, yk864c1 and yk1134e06; class IIb - yk1237d01, which is SL2- spliced, yk856b10, yk1057a6, yk1216e10, yk1103h10 and yk127d10, which is also missing the intron between exon 21 and 22 (not shown); class IIc - yk1264e07; and class III - yk328c9. Only the trans-spliced cDNA clones yk1285a11 and yk1237d01 appear to be full length.