An integral domain R is said to be a UMT-domain if uppers to zero in R
[X] are maximal t-ideals. We show that R is a UMT-domain if and only i
f its localizations at maximal t-ideals have Prufer integral closure.
We also prove that the UMT-property is preserved upon passage to polyn
omial rings. Finally, we characterize the UMT-property in certain pull
back constructions; as an application, we show that a domain has Prufe
r integral closure if and only if all its overrings are UMT-domains.