Subject in article on yours truly (5)
I believe the answer is:
theme
'subject' is the definition.
('theme' can be a synonym of 'subject')
'article on yours truly' is the wordplay.
'article' becomes 'the' (the 'definite article' part of speech).
'on' means one lot of letters go next to another.
'yours truly' becomes 'me'.
'the'+'me'='THEME'
'in' is the link.
(Other definitions for theme that I've seen before include "argument" , "Topic for discussion" , "Topical item" , "Motif, topic" , "basis for variations" .)