Studies on embryonic axis determinants in Xenopus laevis oocytes

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07680806
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Developmental biology
• Research Institution: Kwansei Gakuin University
• Principal Investigator: KINOSHITA Tsutomu Kwansei Gakuin University Faculty of Science Associate Professor, 理学部, 助教授 (30161532)
• Project Period (FY): 1995 – 1996
• Keywords: Xenopus laevis / cytoplasmic factors / determinants / gene cloning / maternal mRNA / PCR / axis formation / localization of mRNA

Research Abstract

In amphibian development, determination of spemann's organizer is a key step for morphogenesis of the embryo. Since molecular mechanism of the organizer formation probably depends on cytoplasmic factors called determinants, molecular cloning of the determinants is a prerequisite step for clarifying mechanism of the embryogenesis. In the present study, we cloned various cDNAs as candidates for determinants, basing on their temporary and spatially regulated expression.
As the first approach, we researched cDNA clones which are transcribed during the period of oogenesis and thereafter translated rapidly. RT-PCR cloning with mix primers for transcription factors showed a cDNA clone, Xext, which has a high homology with human EXT1 gene. As the second approach, we compared molecular species of mRNAs among 4 blastomeres of 8-cell stage embryos. Screening of ovary cDNA library with blastomere-specific cDNA probe selected a candidate clone which encodes a protein of 330 amino acid residues with WD40 repeat within the molecule. As the third approach, we compared mRNAs between normal and hyperdorsalized embryos. Differential display showed a cDNA clone, Xcea, which has a high homology with mouse CEA gene. Functional analyzes of these clones will be performed to evaluate their roles as axis determinants.