Subject of article - Maine (5)
I believe the answer is:
theme
'subject' is the definition.
(theme can mean a topic or subject)
'article maine' is the wordplay.
'article' becomes 'the' (the definite article in English).
'maine' becomes 'me' (abbreviation).
'the'+'me'='THEME'
'of' is the link.
(Other definitions for theme that I've seen before include "Motif - 4 across" , "Topic, leitmotif" , "matter for discussion" , "notedly subject to variation" , "Motif or melody" .)