Takes responsibility for posters put around Cambridge University (6)
I believe the answer is:
admits
'takes responsibility' is the definition.
'admits' can be an answer for 'takes' ('admit' can be a synonym of 'take'). I am not certain of the 'responsibility' bit.
'posters put around cambridge university' is the wordplay.
'posters' becomes 'ads' (poster is a type of advertisement).
'put around' indicates putting letters inside.
'cambridge university' becomes 'MIT' (MIT in Cambridge, Massachusetts).
'ads' enclosing 'mit' is 'ADMITS'.
'for' acts as a link.
Can you help me to learn more?
(Other definitions for admits that I've seen before include "Confesses or allows to enter" , "Owns up or lets in" , "Owns up or grants entrance to" , "grants us access" , "Agrees to the truth of something" .)