The Middle East is a subject of discussion (5)
I believe the answer is:
theme
'subject of discussion' is the definition.
'theme' can be an answer for 'discussion' (I've seen this before). I am unsure of the 'subject of' bit.
'the middle east' is the wordplay.
'middle east' becomes 'me' (abbreviation for Middle East).
'the'+'me'='THEME'
'is a' acts as a link.
Can you help me to learn more?
(Other definitions for theme that I've seen before include "Unifying motif" , "Motif - 4 across" , "Motif or melody" , "issue" , "Topic for discussion" .)