Cloning of a cDNA for Type II Iodothyronine 5' Deiodinase in the House Musk Shrew (Suncus murinus. Insectivora : Soricidae)

国立情報学研究所で電子化したコンテンツを使用している。Two types of iodothyronine 5' deiodinase are known to catalyze the conversion of thyroxine to 3,3',5-triiodothyroine (T3), an active form of thyroid hormone. Our recent study has suggested that type II deiodinase rather than type I is important for the maintenance of plasma T3 as well as the tissue content of T3 in the house musk shrew. The present study aimed to clone cDNA for type II deiodinase and determine the primary structure of DII protein. Total RNA was extracted from the brown adipose tissue in the shrew of Katmandu strain (KAT), where highest DII activity was detected. DII cDNA was cloned in combination by RT-PCR and Rapid Amplification of cDNA Ends (RACE). The alignment of three cloned cDNA fragments includes the entire open reading frame of shrew DII so that the amino acid sequence was deduced. The shrew DII contains two selenocysteins that are essential for the deiodinase activity. The amino acid sequence of the shrew DII showed high homology with that of human (89%), rat (91 %) and mouse (92%). The obtained cDNA would be a proper probe to investigate changes in the DII expression when shrews are exposed to various environments and insults