Expression of functional plant sweet protein thaumatin II in the milk of transgenic mice

Thaumatin is a kind of natural sweet protein which has the characteristics of high sweetness, low calorie, safe and non-toxic, etc. And it has high commercial value in food processing, medicine and other fields. In this study, we employed a sequence that encode thaumatin II, along with goat betacasein 5' and 3' regulatory elements, to construct a mammary gland-specific expression vector. Transgenic mice were generated using pronuclear microinjection, and the expression of thaumatin and its biological activities were assayed in the milk. PCR and southern blot analysis confirmed that the mice harbor thaumatin II transgenes. Thaumatin II retaining their sweetness was expressed in the mammary glands of transgenic mice, as determined by ELISA, western blot and sweetness intensity test. This research describes an initial step in the production of plant protein thaumatin-sweetened milk from large animals such as cow and goat. (C) 2020 Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.