A DYNEIN LIGHT-CHAIN OF SEA-URCHIN SPERM FLAGELLA IS A HOMOLOG OF MOUSE TCTEX-1, WHICH IS ENCODED BY A GENE OF THE T-COMPLEX STERILITY LOCUS

The outer-arm dynein of sea urchin sperm flagella contains six light c hains with molecular masses of 23.2, 20.8, 12.3, 11.5, 10.4 and 9.3 kD a. We have cloned a cDNA for the 12.3 kDa polypeptide (light chain 3) and found that this protein is highly homologous to mouse Tctex1, a pr otein encoded by a member of the multigene family in the t complex reg ion that is involved in male sterility and the development of the germ cells. Tctex1 has recently been shown to be homologous to a light cha in of cytoplasmic dynein. Therefore, the cytoplasmic dynein light chai n has been implicated in the mechanism for the transmission ratio dist ortion (meiotic drive) that is characteristic of t haplotypes in mice. Our present finding, however, indicates that axonemal light chain 3 m ust be considered equally important. (C) 1998 Elsevier Science B.V. Al l rights reserved.