Maternally localized RNA encoding a serine/threonine protein kinase in the ascidian, Halocynthia roretzi

Mech Dev. 1998 Aug;76(1-2):161-3. doi: 10.1016/s0925-4773(98)00100-2.


Maternally localized cytoplasmic determinants play important roles in the embryogenesis of many animals, including ascidians. Cytoplasmic determinants are particularly important in the determination of cell fates, and in the establishment of the embryonic axes. Ascidians, which show mosaic development, are good models for the study of maternal cytoplasmic determinants. Here we report the isolation and characterization of HrPOPK-1 (Halocynthia roretzi posterior protein kinase-1), a putative protein serine/threonine kinase. HrPOPK-1 cDNA was obtained from a Halocynthia roretzi fertilized egg cDNA library by screening for localized RNAs using whole-mount in situ hybridization. HrPOPK-1 mRNA is strongly localized at the posterior pole of embryos. The pattern of HrPOPK-1 mRNA localization during early embryogenesis is identical to that of HrWnt-5 in Halocynthia roretzi, and to those of the posterior end mark (pem) transcripts of Ciona savignyi. In addition, HrPOPK-1 shows zygotic expression in neural tissues at the tailbud stage. These results show that the temporal regulation of HrPOPK-1 transcription is complex.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Embryo, Nonmammalian / enzymology
  • Female
  • Gastrula / enzymology
  • Gene Expression Regulation, Developmental*
  • In Situ Hybridization
  • Molecular Sequence Data
  • Ovum / enzymology
  • Protein-Serine-Threonine Kinases / genetics*
  • Protein-Serine-Threonine Kinases / metabolism
  • Sequence Homology, Amino Acid
  • Urochordata / embryology*
  • Urochordata / genetics*
  • Urochordata / growth & development
  • Zygote


  • HrPOPK-1 protein, Halocynthia roretzi
  • Protein-Serine-Threonine Kinases

Associated data

  • GENBANK/AB014885