Post-transcriptional regulation of H-ferritin mRNA. Identification of a pyrimidine-rich sequence in the 3'-untranslated region associated with message stability in human monocytic THP-1 cells.
We have previously demonstrated that phorbol myristate acetate (PMA) up-regulates H-ferritin gene expression in myeloid cells by stabilization of its message. In the present report, we showed that insertion of the 3'-untranslated region (3'-UTR) of H-ferritin mRNA at the 3'-end of luciferase coding sequence significantly reduced the stability of luciferase mRNA in human monocytic THP-1 cells. However, the half-life of the chimeric transcript was markedly prolonged after PMA treatment. A cytosolic protein factor from THP-1 cells was found to specifically bind to H-ferritin 3'-UTR. PMA treatment of THP-1 cells resulted in the reduction of the RNA binding activity in a time-dependent manner. Deletion analysis and RNase T1 mapping revealed a pyrimidine-rich sequence within the 3'-UTR which interacts with the protein factor. Competition experiments with homoribopolymers further demonstrated the importance of uridines for the binding activity. Point mutations in uridines of the pyrimidine-rich sequence reduced the protein binding to 3'-UTR, while increasing the stability of the chimeric luciferase transcript. Together, these results demonstrate that the pyrimidine-rich sequence in the 3'-UTR is involved in post-transcriptional regulation of H-ferritin gene expression in myeloid cells.
Ai
L S
LS
Division of Cardiovascular Research, Institute of Biomedical Sciences, Academia Sinica, Taipei, Taiwan, R.O.C.
Chau
L Y
LY
D020413:3' Untranslated Regions; D001483:Base Sequence; D002460:Cell Line; D005293:Ferritins / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D009000:Monocytes / Q000378:metabolism; D017354:Point Mutation; D011743:Pyrimidines / Q000378:metabolism*; D012323:RNA Processing, Post-Transcriptional; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*
D020413:3' Untranslated Regions; D011743:Pyrimidines; D012333:RNA, Messenger; D005293:Ferritins