SAN FRANCISCO — Pillsbury represented Mission West Properties Inc. in a sale of its assets that valued the Cupertino-based real estate investment trust at $1.3 billion.

Mission West will sell much of its assets to a joint venture sponsored by San Francisco developer DivcoWest and TPG Real Estate, owned by private equity firm TPG Capital. The deal, which was announced Friday, is expected to close by the end of the year, and Mission West plans to liquidate afterward. DivcoWest and TPG Real Estate will receive about 70 percent of Mission West’s real estate assets, which are concentrated in Silicon Valley, in exchange for paying about $400 million in cash and assuming $398 million of the REIT’s debt and other obligations.