Motorway buries gallery (10)
I believe the answer is:
interstate
'motorway' is the definition.
(I've seen this before)
'buries gallery' is the wordplay.
'buries' becomes 'inters' ('inter' can be a synonym of 'bury').
'gallery' becomes 'tate' (Tate Modern, Tate Britain etc).
'inters'+'tate'='INTERSTATE'
(Other definitions for interstate that I've seen before include "American way" , "American motorway" , "highway" , "road in US" , "between parts of US" .)