MeiraGTx Holdings Plc has entered into a research collaboration and evaluation agreement with Janssen Pharmaceuticals, Inc., facilitated by Johnson & Johnson Innovation LLC.    As part of the agreement, MeiraGTx will use their proprietary riboswitch technology to engineer regulatable gene therapy constructs encoding proprietary gene sequences from Janssen. Evaluation of the performance of these constructs will determine the utility of this approach in future product development. ...