Beast of burden carrying north American (4)
I believe the answer is:
yank
'american' is the definition.
(Yank is an example)
'beast of burden carrying north' is the wordplay.
'beast of burden' becomes 'yak' (I've seen this before).
'carrying' is an insertion indicator.
'north' becomes 'n' ('N' can be a synonym of 'north').
'yak' going around 'n' is 'YANK'.
(Other definitions for yank that I've seen before include "Pull with a sudden movement" , "Pull hard suddenly" , "American (colloq.)" , "Jerk, pull suddenly" , "An informal American - tug him" .)