GENERATION OF A TROPOELASTIN MESSENGER-RNA VARIANT BY ALTERNATIVE POLYADENYLATION SITE SELECTION IN SUN-DAMAGED HUMAN SKIN AND ULTRAVIOLET B-IRRADIATED FIBROBLASTS

The goal of this research was to delineate the post-transcriptional me chanisms responsible for the increased elastin synthesis characteristi c of sundamaged skin. In this study, a unique molecular variant of the tropoelastin mRNA transcript was identified in human sundamaged skin that was derived from the usage of an alternate polyadenylation site. Nonsolar exposed human skin expressed one tropoelastin mRNA species wh ereas sundamaged human skin expressed the primary tropoelastin mRNA an d a larger, alternate tropoelastin mRNA formed from the utilization of a second polyadenylation site. Cultured human skin fibroblasts expres sed both tropoelastin transcripts and in vitro UV treatment increased the amount of the unique tropoelastin mRNA. Hairless mouse skin (norma l and UV treated) expressed the primary tropoelastin transcript althou gh UV irradiation increased the length of its poly (A) tail two-fold. Therefore, UV radiation may stimulate elastin production by affecting polyadenylation site selection and the poly (A) tail length of tropoel astin mRNA. (C) 1998 Academic Press.