Molecular analysis of a cytoplasmic factor essential for pole cell formation in Drosophila embryos

This article reviews recent analytical studies of cytoplasmic factors involved in a mechanism underlying pole cell formation in Drosophila embryogenesis. Polar plasm, or germ plasm, includes sources of two independent functions in the germ-line segregation from the somatic line: pole cell formation and commitment of pole cells to germ cells. The UV-caused inability of pole cell formation in embryos was restored by poly(A)+ RNA, of which cDNA was cloned. The nucleotide sequence of the cDNA was highly homologous with mitochondrial large rRNA.