Abstract
In Drosophila, the factors with sufficient ability to establish germ line are localized in a histologically remarkable region in egg cytoplasm, of germ plasm. Mitochondrial large ribosomal RNA (mtlrRNA) has been indentified as a factor which can rescue embryos from uvcaused inability to form pole cells, or the germline progeniter. MtlrRNA is transported out of mitochondria only in germ plasm. The extra-mitochomdrial mtlrRNA is tightly associated with polar granules, a distinctive organelle of germ plasm. We have recently found that the injection of targeted ribozymes against the extra-mitochondrial mtlrRNA into early embryos results in their failure to form pole cells. These results clearly show that mtlrRNA functions as a factor to form pole cells.
