SPATIAL-DISTRIBUTION OF COLLAGEN TYPE-I MESSENGER-RNA IN PARACENTROTUS-LIVIDUS EGGS AND EMBRYOS

We have identified the presence of type I collagen (COLL1 alpha) mRNA in Paracentrotus lividus unfertilized egg, indicating a maternal origi n of this mRNA. By in situ whole mount hybridization the spatial distr ibution of COLL1 alpha mRNA in egg and embryo at different development al stages was established. Moreover, the presence of COLL1 alpha gene in Paracentrotus lividus genome was analyzed by Southern blot experime nts. The localization pattern indicates that the maternal mRNA is plac ed in the fertilized egg in a fixed position, relative to the embryoni c axes. Furthermore, the embryonic expression is spatially restricted during development, suggesting involvement in sea urchin embryo cell s pecification events. The presence of two bands in Southern blot hybrid ization may indicate that two genes specific for COLL1 alpha are prese nt in the sea urchin genome. (C) 1997 Academic Press.