Evidence That a Specific Interaction Between an 18-Base cis-Element in the 5′-Untranslated Region of Human Folate Receptor-α mRNA and a 46-kDa Cytosolic trans-Factor is Critical for Translation *

摘要: Folate receptors (FR) are inversely regulated by the extracellular folate concentration at translational level in cervical carcinoma cells. Accordingly, potential for interaction of cis-elements FR-α mRNA and trans-factors these cells was determined. Gel-shift assays identified two signals that were specifically derived from cytosolic proteins with 5′-untranslated region mRNA. RNase T1 mapping revealed RNA sequences interacting located between nucleotides −133 to −116 (18-bases) −158 (43-bases), upstream translation start site. However, selective H cleavage indicated 18-base sequence cis-element. The RNA-protein competed poly(C), but not poly(U), homopolymers. UV cross-linking Northwestern blot analysis confirmed 46-kDa proteins. An antisense oligodeoxynucleotide complementary cis-element quenched also completely inhibited without changing its stability. Thus, likely have an important role regulation FR. In addition, because widely distributed expressing little no FR-α, species probably additional functions unrelated