Tiny characters run around US shopping centre (5,5)
I believe the answer is:
small print
'tiny characters run' is the definition.
The definition suggests a singular noun which matches the answer.
'around us shopping centre' is the wordplay.
'around' means one lot of letters goes inside another.
'us' becomes 'sprint' (I am not sure about this - if you are sure you should believe this answer much more).
'shopping centre' becomes 'mall' (a mall is a large shopping complex).
'sprint' enclosing 'mall' is 'SMALL PRINT'.
Can you help me to learn more?
(Other definitions for small print that I've seen before include "Inconspicuous part of agreement" , "Words often ignored" , "You may regret not reading this!" , "Be careful to read this" , "A trap for the unwary consumer" .)