IDENTIFICATION OF THE T-COMPLEX-ENCODED CYTOPLASMIC DYNEIN LIGHT-CHAIN TCTEX1 IN INNER ARM-I1 SUPPORTS THE INVOLVEMENT OF FLAGELLAR DYNEINSIN MEIOTIC DRIVE

The cytoplasmic dynein light chain Tctex1 is a candidate for one of th e distorter products involved in the non-Mendelian transmission of mou se t haplotypes. It has been unclear, however, how the t-specific muta tions in this protein, which is found associated with cytoplasmic dyne in in many tissues, could result in a male germ cell-specific phenotyp e. Here, we demonstrate that Tctex1 is not only a cytoplasmic dynein c omponent, but is also present both in mouse sperm and Chlamydomonas fl agella. Genetic and biochemical dissection of the Chlamydomonas flagel lum reveal that Tctex1 is a previously undescribed component of inner dynein arm Il. Combined with the recent identification of another puta tive t complex distorter, Tctex2, within the outer dynein arm, these r esults support the hypothesis that transmission ratio distortion (meio tic drive) of mouse t haplotypes involves dysfunction of both flagella r inner and outer dynein arms but does not require the cytoplasmic iso zyme.