According to this doc, Bukko Island Sushi and Grill will be one of the first tenants in 777 Center. According to rumors I have heard, it will be a Japanese style grill with a sushi bar in it. Sushi won't be the main focus.
UPDATE: Just received more info!
"The new 777 building in Midtown has finished construction and Japanese restaurant Bukko Island Sushi and Grill is the first to sign a lease. Bukko will bring a twist to traditional sushi and Japanese food found throughout the Northern Nevada area. Chef Betto Fierro, former chef of Hiroba in Reno, NV, is one of two owners and will be the head chef for the new Bukko Island Sushi and Grill restaurant set to open before the end of the year. All sushi will be à la carte with no all you can eat option while various other Japanese dishes will be available to satisfy various dining patrons. The restaurant is featured on the second floor of the building with a roll up door out to the deck and windows facing south west looking out to Mt. Rose. There will be a sushi bar, dining area and full bar within the restaurant. According to Fierro, the restaurant atmosphere will allow for a casual or up-scale dining experience whether stopping in for lunch while at work or going out to dinner for a special occasion."