Take over American university vacant readership (5)
I believe the answer is:
usurp
'take over' is the definition.
('usurp' can be a synonym of 'take over')
'american university vacant readership' is the wordplay.
'american' becomes 'us'.
'university' becomes 'u'.
'vacant' suggests removing the centre.
'readership' with its middle removed is 'rp'.
'us'+'u'+'rp'='USURP'
(Other definitions for usurp that I've seen before include "Take (power) by force or illegally" , "Appropriate without authority" , "Depose illegally" , "Seize wrongfully" , "Seize possession of" .)