hnRNP L binds to CA repeats in the 3'UTR of bcl-2 mRNA.
We previously reported that the CA-repeat sequence in the 3'-untranslated region (3'UTR) of bcl-2 mRNA is involved in the decay of bcl-2 mRNA. However, the trans-acting factor for the CA element in bcl-2 mRNA remains unidentified. The heterogeneous nuclear ribonucleoprotein L (hnRNP L), an intron splicing factor, has been reported to bind to CA repeats and CA clusters in the 3'UTR of several genes. We reported herein that the CA repeats of bcl-2 mRNA have the potential to form a distinct ribonuclear protein complex in cytoplasmic extracts of MCF-7 cells, as evidenced by RNA electrophoretic mobility shift assays (REMSA). A super-shift assay using the hnRNP L antibody completely shifted the complex. Immunoprecipitation with the hnRNP L antibody and MCF-7 cells followed by RT-PCR revealed that hnRNP L interacts with endogenous bcl-2 mRNA in vivo. Furthermore, the suppression of hnRNP L in MCF-7 cells by the transfection of siRNA for hnRNP L resulted in a delay in the degradation of RNA transcripts including CA repeats of bcl-2 mRNA in vitro, suggesting that the interaction between hnRNPL and CA repeats of bcl-2 mRNA participates in destabilizing bcl-2 mRNA.
Lee
Dong-Hyoung
DH
Department of Biochemistry, College of Medicine, The Catholic University of Korea, 505 Banpo-Dong, Seocho-gu, Seoul 137-701, Republic of Korea.
Lim
Mi-Hyun
MH
Youn
Dong-Ye
DY
Jung
Seung Eun
SE
Ahn
Young Soo
YS
Tsujimoto
Yoshihide
Y
Lee
Jeong-Hwa
JH
D020413:3' Untranslated Regions / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D034664:Heterogeneous-Nuclear Ribonucleoprotein L / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics*; D020871:RNA Stability; D012091:Repetitive Sequences, Nucleic Acid
D020413:3' Untranslated Regions; D034664:Heterogeneous-Nuclear Ribonucleoprotein L; D019253:Proto-Oncogene Proteins c-bcl-2