The upstream stem-loop domain of the 3' untranslated region of apolipoprotein II mRNA binds the estrogen-regulated mRNA stabilizing factor.
Apolipoprotein II (apoII), a component of the very low density lipoprotein (VLDL) particle, is a yolk protein expressed in the liver in response to estrogen. Its expression is modulated by estrogen-mediated stimulation of transcription as well as stabilization of its mRNA. This stabilization is due to the estrogen-regulated mRNA stabilizing factor (E-RmRNASF) [Cell. Mol. Biol. Res. 41 (1995) 583). E-RmRNASF protects apoII mRNA from targeted endonucleolytic degradation. The expression of E-RmRNASF itself is under estrogenic control. The hepatic expression of E-RmRNASF is also modulated by certain estrogenic and anti-estrogenic non-steroidal environmental xenobiotics [Biochem. Pharmacol. 53 (1997) 1425]. Studies involving RNA affinity-based depletion of mRNA stabilization activity indicated that E-RmRNASF binds to apoII mRNA. E-RmRNASF binds apoII mRNA in a region-specific manner. The region of binding has been narrowed down to the upstream domain of stem-loop secondary structure spanning nucleotides (nt) 402-558 in the 3' untranslated region (3'UTR). A RNA affinity chromatography procedure using this portion of apoII mRNA was utilized for the purification of E-RmRNASF. A gel filtration (GF) chromatography step preceding the RNA affinity chromatography was required for additional enrichment of E-RmRNASF. A functional assay involving the in vitro stabilization of apoII mRNA from degradation was utilized to detect E-RmRNASF during chromatography. E-RmRNASF appears to be a protein of apparent molecular weight of 20-25kDa visualized by SDS polyacrylamide gel electrophoresis.
Ratna
Warren N
WN
Division of Pharmacology, Toxicology and Medicinal Chemistry, Arnold and Marie Schwartz College of Pharmacy, Long Island University, 1 University Plaza, Brooklyn, NY 11201, USA. warren.ratna@netscape.net
Oyeamalu
Chioma
C
D020413:3' Untranslated Regions; D000818:Animals; D001053:Apolipoproteins / Q000235:genetics* / Q000378:metabolism*; D001667:Binding, Competitive; D019921:Biotinylation; D002645:Chickens; D002850:Chromatography, Gel; D003600:Cytosol / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D008099:Liver; D011485:Protein Binding; D011498:Protein Precursors / Q000235:genetics* / Q000378:metabolism*; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D020871:RNA Stability; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors
D020413:3' Untranslated Regions; D001053:Apolipoproteins; D011498:Protein Precursors; D012333:RNA, Messenger; C054949:apolipoprotein II