Abstract
Analysis of cDNA encoding the double-stranded ribonuclease (Bm-dsRNase) of the silkworm, Bombyx mori, elucidated a possible conclusion that the 41kDa mature dsRNase is produced from the 45kDa precursor protein in the middle midgut tissue by post-translational processing. To strengthen this speculation, the 41kDa protein was produced in vitro: the 43kDa-45kDa protein-rich fraction was partially purified by gel filtration and then treated with bovine trypsin. Specific conversion of the 43kDa and 45kDa proteins into the enzymically-active 41kDa protein was demonstrated by a Western blot analysis and dsRNase activity assay, strongly supporting that the 41kDa Bm-dsRNase is produced in vivo by the limited proteolysis that was induced by an endogenous trypsin-like enzyme, and immediately released into midgut lumen.
© 2010 by Japan Academic Association for Copyright Clearance (Except in the USA), Copyright Clearance Center, Inc. (In the USA)
