ASSOCIATION OF CENTRIOLES WITH THE MARGINAL BAND IN SKATE ERYTHROCYTES

Abstract

Centrioles are associated with the marginal bands (MBs) in certain invertebrate erythrocytes, functioning as organizing centers for MB reassembly (Nemhauser et al., 1983). However, a similar association has not been observed previously in erythrocytes of vertebrates. Detergent-lysed erythrocytes ("cytoskeletons")of the skate Raja erinacea contain centrioles visible as paired dense dots in phase contrast. In uranyl acetate-stained whole mounts and in thin sections (TEM) they exhibit typical right-angle orientation and 9-triplet ultrastructure. Although the centriole pairs in some cytoskeletons are distant from the MB, surveys of their distribution in preparations from different animals indicates that it is non-random, with the majority adjacent to the MB or less than 1 µm from it. Many of the centriole pairs appear to be attached to MB microtubules, or have microtubules extending from them toward the MB. In rare instances, pointed cytoskeletons are observed with the centrioles at the apex from which fibers radiate, suggesting a morphogenetic function. The observations support the possibility that centrioles function during MB biogenesis in differentiating vertebrate erythrocytes, with loss of functional location as the cells mature.