Alternative RNA splicing generates transcripts encoding a thorax-specific isoform of Drosophila melanogaster myosin heavy chain.
Genomic and cDNA sequencing studies show that transcripts from the muscle myosin heavy-chain (MHC) gene of Drosophila melanogaster are alternatively spliced, producing RNAs that encode at least two MHC isoforms with different C termini. Transcripts encoding an MHC isoform with 27 unique C-terminal amino acids accumulate during both larval and adult muscle differentiation. Transcripts for the second isoform encode one unique C-terminal amino acid and accumulate almost exclusively in pupal and adult thoracic segments, the location of the indirect flight muscles. The 3' splice acceptor site preceding the thorax-specific exon is unusually purine rich and thus may serve as a thorax-specific splicing signal. We suggest that the alternative C termini of these two MHC isoforms control myofilament assembly and may play a role in generating the distinctive myofilament organizations of flight muscle and other muscle types.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D004247:DNA / Q000032:analysis; D004331:Drosophila melanogaster / Q000201:enzymology*; D004720:Endonucleases / Q000378:metabolism; D005786:Gene Expression Regulation; D007527:Isoenzymes / Q000235:genetics*; D009218:Myosins / Q000235:genetics*; D012313:RNA / Q000378:metabolism; D012326:RNA Splicing; D015719:Single-Strand Specific DNA and RNA Endonucleases; D014158:Transcription, Genetic
D007527:Isoenzymes; D012313:RNA; D004247:DNA; D004720:Endonucleases; D015719:Single-Strand Specific DNA and RNA Endonucleases; D009218:Myosins