Generation of a Tropoelastin mRNA Variant by Alternative Polyadenylation Site Selection in Sun-Damaged Human Skin and Ultraviolet B-Irradiated Fibroblasts

Abstract

The goal of this research was to delineate the posttranscriptional mechanisms responsible for the increased elastin synthesis characteristic 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 whereas sundamaged human skin expressed the primary tropoelastin mRNA and a larger, alternate tropoelastin mRNA formed from the utilization of a second polyadenylation site. Cultured human skin fibroblasts expressed both tropoelastin transcripts and in vitro UV treatment increased the amount of the unique tropoelastin mRNA. Hairless mouse skin (normal and UV treated) expressed the primary tropoelastin transcript although 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 tropoelastin mRNA.