Supports in the construction of a dais (4)
I believe the answer is:
aids
'supports' is the definition.
('aid' can be a synonym of 'support')
'construction of a dais' is the wordplay.
'construction of' indicates anagramming the letters (I've seen 'construction' mean this (answer constructed from certain letters)).
'dais' anagrammed gives 'AIDS'.
'in the' acts as a link.
(Other definitions for aids that I've seen before include "Said to be a modern plague" , "Said to be an international disease" , "Condition following infection with HIV virus" , "Assists" , "Said to be a dread modern disease" .)