RESTON, VA-Boston Properties has staked out more ground in two of its stronghold markets—San Francisco and the Washington, DC area. The San Francisco deal, not surprisingly given its scope, has captured much attention. Briefly, the company plans to build a 27-story office tower at 535 Market St. It also is paying $27 million to buy what it terms is the last remaining parcel of land in the urban core of Reston Town Center.

Reston has seen a lot of activity in recent weeks—to name one example, RTC Partnership LLC is moving forward with what will be the tallest building in the submarket — 1760 Reston Pkwy. The company is in the process of collecting bids for the tower, having tapped Transwestern as its exclusive broker recently.

Garrison Investment Group, as another example, is moving forward with a spec development project at 10790 Parkridge Blvd., a 205,000 square foot office building with a data center and training space on the concourse level. The company decided to develop several small suites ranging in size from 3,000 to 5,000 square feet due to Garrison’s success in leasing out Reston Corner with a similar strategy, Cassidy Turley’s Tim Summers told in an earlier interview.

Still, though, a more ambitious project – such as the type that Boston Properties is likely to develop – may be further off. RTC, for instance, is not moving forward with its tower until it has some leases in place, Transwestern’s Matt Bundy told earlier this week.

Fundamentals in San Francisco—not to state the obvious—are clearly better.

The $71 million it paid 535 Mission includes the foundation work that seller Beacon Capital had already completed and the steel it had acquired to build a planned office tower there before suspending work in the fall of 2008. BXP says it’s aiming for LEED Gold certification on the 378-foot office tower, for which it expects to start construction later this month.

When completed, it will offer about 307,000 rentable square feet of office and retail space, according to a release. The tower is expected to cost $215 million to build; a fall 2014 completion date is expected.

At the Reston Town Center site, commercially zoned for 250,000 square feet of office space, BXP is evaluating a potential mixed-use development plan, which could include residential uses as well as commercial uses. The deal is expected to close in the first quarter.