Transgene analysis proves mRNA trans-splicing at the complex mod(mdg4) locus in Drosophila.
The Drosophila BTB domain containing gene mod(mdg4) produces a large number of protein isoforms combining a common N-terminal region of 402 aa with different C termini. We have deduced the genomic structure of this complex locus and found that at least seven of the mod(mdg4) isoforms are encoded on both of its antiparallel DNA strands, suggesting the generation of mature mRNAs by trans-splicing. In transgenic assays, we demonstrate the ability of Drosophila to produce mod(mdg4) mRNAs by trans-splicing of pre-mRNAs generated from transgenes inserted at distant chromosomal positions. Furthermore, evidence is presented for occurring of trans-splicing of mod(mdg4)-specific exons encoded by the parallel DNA strand. The mod(mdg4) locus represents a new type of complex gene structure in which genetic complexity is resolved by extensive trans-splicing, giving important implications for genome sequencing projects. Demonstration of naturally occurring trans-splicing in the model organism Drosophila opens new experimental approaches toward an analysis of the underlying mechanisms.
Dorn
R
R
Institute of Genetics, Biologicum, Martin Luther University, Halle, Germany. dorn@genetik.uni-halle.de
Reuter
G
G
Loewendorf
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D018076:DNA, Complementary / Q000235:genetics; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics*; D005091:Exons / Q000235:genetics; D019476:Insect Proteins / Q000096:biosynthesis / Q000235:genetics*; D007438:Introns / Q000235:genetics; D008957:Models, Genetic; D008969:Molecular Sequence Data; D020033:Protein Isoforms / Q000096:biosynthesis / Q000235:genetics*; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics*; D019076:Transgenes
D018076:DNA, Complementary; D029721:Drosophila Proteins; D019476:Insect Proteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D014157:Transcription Factors; C101384:mod(mdg4) protein, Drosophila