| Research Abstract |
We have constructed cDNA libraries from immortalized cell lines of lymphocytes or fibroblasts isolated from the following 14 species of primates : Pan troglodytes, Pan paniscus, Gorilla gorilla, Pongo pygmaeus, Hylobates syndactylus, Hylobates concolor, Cercopithecus mitis, Erythrocebus patas, Presbytis entellus, Colobus polykomos, Callithrix jachus, Saguinus oedipus, Tarsius bancanus, and Galago senegalensis. In order to examine tissue-NON-specific gene expression, we tested expression of visual pigment gene in the cDNA libraries. No expression was detected in all libraries. Visual pigments comprise a gene family, which shows a variety of light absorption characteristics, and exhibit remarkable evolutionary diversity among animals possibly due to adaptation to particular light environment. Generally only single type of visual pigment is expressed in a given photoreceptor cell. Therefore, it is of great importance to examine the variation of visual pigments among animals and mechanism
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of cell-type-specific gene expression. We examined genomic organization and spectral properties of visual pigment genes of New World primates, rodents, birds, and fish. By applying molecular cloning, Southern hybridization, chromosome FISH, and visual pigment regeneration to common marmoset, we found that the tri-allelic single-locus X-chromosome model on the red-green visual pigments holds for marmosets under the unique phenomenon, known as blood chimerism. Applying the same methods, we found owl monkeys to have multiple green visual pigment genes on Y chromosome, most of which appeared to be nonfunctional. Capuchin monkeys also appeared to have two red-green gene loci based on the result of Southern hybridization. We cloned all visual pigment genes from pigeon, one of which corresponded to UV-sensitive visual pigment.
Absorption spectra of UV pigments were also determined for mouse, rat, and goldfish. These results greatly deepened our understanding of evolution and diversity of vertebrate visual pigments and visual systems. Less
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