Writer's brief life story about queen (4)
I believe the answer is:
biro
'writer's' is the definition.
(type of pen, something which writes)
'brief life story about queen' is the wordplay.
'brief life story' becomes 'bio' (short for biography; 'brief' suggests an abbreviation).
'about' means one lot of letters goes inside another.
'queen' becomes 'r' (abbreviation for regina, e.g. in ER ).
'bio' enclosing 'r' is 'BIRO'.
(Other definitions for biro that I've seen before include "Laszlo Jozsef -, ballpoint pen inventor" , "Pocket item" , "Type of ballpoint pen" , "writer" , "Writing implement" .)