| Research Abstract |
The present study lias beeti uridertaleii as orie of the efforts to accumulate knowledge ori the origin of multicellular animals utilizing collagen and its genes as probes. It has beeti generally l (now that all title multicellular animals from the most primitive species, sponges, to tie most evolved one, human, contain collagen-as one of the major proteins, but neither plants nor unicellular organisms do not, suggesting that collagen and its genes play some important role-, s during evolutiotin from multi-icellular organisms to multicellular animals. The present author has developed for 2 years studies on collagen and its genes from the comparative point of view to malke a progress in understanding the process of establishment of multicellularity during animal evolution. The major results are described below.
1. Studying on collagen and its genes of sea urchins.
Collagen was purified from the tests of two species of sea urchin, Hemicentrotus pml. cherrimus and StrpLn loqentrodus purpura
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tus. Three alpha chains were identified and named alpha 120, alpha 90 and alpha 140, respectively. cDNA, Hpcol1, was cloned, which codes alpha 120 and alpha 140. Sequences of Hpcol1 were determined in its full length.
2. Studies on collagen genes of Mesozoans.
Genome DNA of Dicyema misakiense, a Mesozoati, whose body structure is believed to be simplest among animals, was analyzed for ttie presence of base sequences homologous to those of lipcoll with the Southern blotting. It was found that the animal does not contain such sequences.
3. Studies on sponge collagen
Collagen peptides with a molecular weight or 581 (were found to be synthesized during reaggregation of dissociated sponge cells. This peptide seems to play some critical roles during organization of sponge cells.
4. Comparative studies of fibroblasts from different organs.
Fibroblasts, one of tile major cell species that synthesize collagen, were obtained from three different organs ; skin, lung and heart and cultured in vito. It was found that fibroblasts show organ-dependent characters as to rate of proliferation, collagen gel contracting ability and protein synthesis patterns. Less
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