Press employee — sort seen with gun dog (10)
I believe the answer is:
typesetter
'press employee' is the definition.
(someone setting type for a printing press)
'sort seen with gun dog' is the wordplay.
'sort' becomes 'type' (type is a kind of sort).
'seen with' says to put letters next to each other.
'gun dog' becomes 'setter' (setter is a kind of gun dog).
'type'+'setter'='TYPESETTER'
(Other definitions for typesetter that I've seen before include "Former newspaper employee" , "one putting printed words in right order?" , "One doing composition" , "Press worker" , "Printing expert" .)