I have this lens and use it on a Nikon D300. As popo mentions, no you cannot go shutter-priority, per se. From the perspective that shutter-PRIORITY means that the camera can adjust aperture and other variable to adjust to your selected shutter-speed - you can't.
However, this does not mean that you cannot select your shutter speed. You can go full manual and still have auto-ISO adjust to your choices.
Keep in mind that your camera has to be able to accept non-CPU lens data-entry (made by you), otherwise it cannot calculate exposure at all! On the Nikon, I enter 85mm and f1.4 as the non-CPU specs, and the camera can find the correct exposure automatically in Aperture mode.
This lens is great for the price! It cannot take screw-in filters, mind you. But action is very smooth, construction is very solid and being able to adjust the aperture the old way, by rotating the aperture ring, is just so much more intuitive than some wheel in the body - I think anyway.
Image quality is superb, but it's not easy to find focus @ F1.4 with such a slim DOF. If I used this lens more often, I'd put one of those split-prism focus screen on my camera similar to what we had with film cameras. But if you can make it all come together, it can produce spectacular results for you and you save a lot of money, going with this lens.
Hope to see some shots from you, with this lens sometime!