A joint venture formed by retail giant General Growth Properties Inc. and Ashkenazy Acquisition Corp. is acquiring a 20 percent interest in the Miami Design District from the master developer for $280 million, which values the entire project at $1.4 billion.

Miami Design District Associates, a partnership between developer Craig Robins’ Dacra and private equity fund L Real Estate, is building a mixed-use project that will take up large swaths between Northeast 38th and 42nd streets from North Miami Avenue to Northeast Second Avenue.