IDENTIFICATION OF DYNEIN HEAVY-CHAIN GENES EXPRESSED IN HUMAN AND MOUSE TESTIS - CHROMOSOMAL LOCALIZATION OF AN AXONEMAL DYNEIN GENE

Dynein heavy chains are involved in microtubule-dependent transport pr ocesses. While cytoplasmic dyneins are involved in chromosome or vesic le movement, axonemal dyneins are essential for motility of cilia and flagella. Here we report the isolation of dynein heavy chain (DHC)-lik e sequences in man and mouse. Using polymerase chain reaction and reve rse-transcribed human and mouse testis RNA cDNA fragments encoding the conserved ATP binding region of dynein heavy chains were amplified. W e identified 11 different mouse and eight human dynein-like sequences in testis which show high similarity to known dyneins of different spe cies such as rat, sea urchin or green algae. Sequence similarities sug gest that two of the mouse clones and one human clone encode putative cytoplasmic dynein heavy chains, whereas the other sequences show high er similarity to axonemal dyneins. Two of nine axonemal dynein isoform s identified in the mouse testis are more closely related to known out er arm dyneins, while seven clones seem to belong to the inner arm dyn ein group. Of the isolated human isoforms three clones were classified as outer arm and four clones as inner arm dynein heavy chains. Each o f the DHC cDNAs corresponds to an individual gene as determined by Sou thern blot experiments. The alignment of the deduced protein sequences between human (HDHC) and mouse (MDHC) dynein fragments reveals higher similarity between single human and mouse sequences than between two sequences of the same species. Human and mouse cDNA fragments were use d to isolate genomic clones. Two of these clones, gNDHC7 and gMDHC7, a re homologous genes encoding axonemal inner arm dyneins. While the hum an clone is assigned to 3p21, the mouse gene maps to chromosome 14. (C ) 1997 Elsevier Science B.V.