A FAMILY OF DYNEIN GENES IN DROSOPHILA-MELANOGASTER

We report the identification and initial characterization of seven Duo sophila dynein heavy chain genes. Each gene is single copy and maps to a unique genomic location. Sequence analysis of partial clones reveal s that each encodes a highly conserved portion of the putative dynein hydrolytic ATP-binding site in dyneins that includes a consensus phosp hate-binding (P-loop) motif. One of the clones is derived from a Droso phila cytoplasmic dynein heavy chain gene, Dhc64C, that shows extensiv e amino acid identity to cytoplasmic dynein isoforms from other organi sms. Two other Drosophila dynein clones are 85 and 90% identical at th e amino acid level to the corresponding region of the beta heavy chain of sea urchin axonemal dynein. Probes for all seven of the dynein-rel ated sequences hybridize to transcripts that are of the appropriate si ze, similar to 14 kilobases, to encode the characteristic high molecul ar weight dynein heavy chain polypeptides. The Dhc64C transcript is re adily detected in RNA from ovaries, embryos, and testes. Transcripts f rom five of the six remaining genes are also detected in much lesser a mounts in tissues other than testes. All but one of the dynein transcr ipts are expressed at comparable levels in testes suggesting their par ticipation in flagellar axoneme assembly and motility.