Molecular structure of dynein and motility of a giant sperm axoneme provided with only the outer dynein arm

摘要: The peculiar sperm axoneme of the dipteran Asphondylia ruebsaameni is characterized by an extraordinarily high number microtubule doublets (up to 2,500) arranged in double parallel spirals. Doublets inner row each spiral are tilted, so that their outer arms point towards B-tubule next doublet row. provided with only arm, and no structure related central pair/radial spoke complex present. When analyzed quick-freeze, deep-etch electron microscopy, dynein was shown share same organization described other organisms; however, it appears be somewhat more than previously found a species,Monarthropalpus flavus, since foot region displays globular extra-domain intercalated between adjacent arms. Treatment demembranated ATP vanadate induced conformational changes SDS-page suggested presence single molecular weight band or, gels best electrophoretic resolution, two very closely spaced bands. This polypeptide positively reacted polyclonal antibody raised against specific amino acid sequence located phosphate-binding loop catalytic site. Dynein heavy chain-related DNA sequences corresponding were amplified RT-PCR. Two distinct fragments (Asph-ax1 Asph-ax2) encoding axonemal identified. Southern blot analysis performed on genomic using these as probe showed they part different genes. An intron identified Asph-ax1 fragment at position site nucleotide deletion putative pseudogene Monarthropalpus. spermatozoa exhibited vivo whirling movement both deferent duct spermatheca, but unable undergo processive vitro. They propagated three-dimensional wave when constrained bent configuration some mechanical means. phylogenetic relationships species, Monarthopalpus Asphondylia, based biochemical data also discussed. Cell Motil. Cytoskeleton 50:129–146, 2001. © 2001 Wiley-Liss, Inc.