A collaborative research group led by Assistant Professor Yoshiyasu Ishimaru and Associate Professor Taro Mito in the Department of Biomolecular Function, Faculty of Bioresources and Industry, Tokushima University, has discovered a new mechanism for controlling the change (transformation) from larvae to adults. Announced.This result is a result of joint research between Tokushima University and Okayama University.
Juvenile hormone (JH) is a hormone that promotes the growth of larvae and suppresses metamorphosis into adults, and it is necessary to suppress the synthesis of JH for metamorphosis.It has been reported that methyltransferase (jhamt) is important for the JH synthesis, but the mechanism of regulation of jhamt expression was unknown.
This time, the research group used crickets to investigate the function of the TGF-β signal, which is one of the major cell proliferation signals. When the function of Dpp / gbb, which is a TGF-β family factor, was suppressed, the JH concentration decreased due to the decreased expression of jhmat, and the body size was reduced and precocious metamorphosis occurred at all stages of the last-instar larvae.In addition, in individuals that suppressed the function of Myoglianin, which is a TGF-β family factor, jhamt expression and JH level increased and could not be transformed into adults, and excessive molting was repeated as larvae, eventually growing into giant larvae. bottom.From this, the Dpp / gbb signal positively regulates jhamt expression (ON), while the Myoglianin signal functions as a negative (OFF) inhibitory action, which induces metamorphosis and adultification. Turned out.Furthermore, we clarified the molecular mechanism of new JH synthesis that suppresses jhamt expression.
In the future, we will proceed with the development of a new pest control agent (insect growth inhibitor) focusing on the TGF-β signal pathway, and insects (especially crickets) are attracting attention as a new protein source. It will be applied to the production of edible and feed for crickets.On the other hand, Myoglianin is a muscle formation inhibitor, and we hope to contribute to the elucidation of the mechanism of muscle mass increase due to the inhibition.