Multiple Functions of Nuclear DNA Helicase II （RNA Helicase A） in Nucleic Acid Metabolism

Nuclear DNA helicase Ⅱ (NDH Ⅱ),or RNA helicase A (RHA), was initially discovered in mammals by conventional protein purification methods. Molecular cloning identified apparent sequence homologies between NDH Ⅱ and a Drosophila protein named maleless (MLE),the latter being essential for the Drosophila X-chromosome dosage compensation. Increasing amounts of evidence suggest that NDH Ⅱ is involved in multiple aspects of cellular and viral DNA and RNA metabolism. Moreover the functions of NDH Ⅱ may have potential clinical implications related to viral infection, autoimmune diseases, or even tumorigenesis.