directive.js

app.directive('isolated', function() {
  return {
    scope: {
      message: '='
    },
    template: '<input ng-model="message.content"><span>{{message.content}}</span>'
  };
});

view.html

<div ng-controller="EditController">
  <input ng-model="parentMessage.content">
  <span>{{parentMessage.content}}</span>
  <div isolated message="parentMessage"></div>
</div>