LOCALIZATION OF RIBOSOMAL-PROTEIN L5 MESSENGER-RNA IN MYOPLASM DURINGASCIDIAN DEVELOPMENT

We have isolated and characterized the cDNA clone ScYC26a from the asc idian Styela clava based on its relationship to the non-coding yellow crescent (YC) RNA. The ScYC26a mRNA has a long 5' non-coding sequence that is complementary to YC RNA. The deduced amino acid sequence indic ates that ScYC26a encodes the ribosomal protein L5. The ScYC26a mRNA i s probably encoded by a single copy gene, which shares genomic DNA res triction fragments with the gene encoding YC RNA, suggesting that the ScYC26a and YC genes are closely linked in the S. clava genome. Northe rn blot hybridization showed that S. clava eggs and embryos contain ma ternal ScYC26a mRNA and that zygotic ScYC26a transcripts do not accumu late until after metamorphosis. In situ hybridization showed that mate rnal ScYC26a mRNA is localized in the myoplasm and is segregated prima rily to the muscle cell lineages during embryogenesis. The interaction of YC and ScYC26a transcripts may be involved in translational contro l or localization of L5 mRNA in the myoplasm. (C) 1996 Wiley-Liss, Inc .