A CYTOPLASMIC DYNEIN HEAVY-CHAIN IN SEA-URCHIN EMBRYOS

By making the hypothesis that the pattern of conserved sequence residu es in the vicinity of the hydrolytic ATP-binding site of dynein would resemble that in myosins from a broad variety of sources, we designed degenerate oligonucleotide primers capable of amplifying this region o f multiple dynein isoforms from sea urchin embryo poly(A)+ RNA. Quanti fication of the expression of two of these dynein isoforms has shown t hat the level of mRNA encoding for the beta-heavy chain, like that of tubulin, increases 2-3-fold after deciliation of the embryos, whereas the expression of the second dynein isoform, like that of actin, is es sentially unaffected. This second isoform is believed to be the cytopl asmic dynein of sea urchin embryos.