The RNA recognition motif domains of RBM5 are required for RNA binding and cancer cell proliferation inhibition.
RBM5 is a known putative tumor suppressor gene that has been shown to function in cell growth inhibition by modulating apoptosis. RBM5 also plays a critical role in alternative splicing as an RNA binding protein. However, it is still unclear which domains of RBM5 are required for RNA binding and related functional activities. We hypothesized the two putative RNA recognition motif (RRM) domains of RBM5 spanning from amino acids 98-178 and 231-315 are essential for RBM5-mediated cell growth inhibition, apoptosis regulation, and RNA binding. To investigate this hypothesis, we evaluated the activities of the wide-type and mutant RBM5 gene transfer in low-RBM5 expressing A549 cells. We found that, unlike wild-type RBM5 (RBM5-wt), a RBM5 mutant lacking the two RRM domains (RBM5-ΔRRM), is unable to bind RNA, has compromised caspase-2 alternative splicing activity, lacks cell proliferation inhibition and apoptosis induction function in A549 cells. These data provide direct evidence that the two RRM domains of RBM5 are required for RNA binding and the RNA binding activity of RBM5 contributes to its function on apoptosis induction and cell growth inhibition.
Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China.
Lei
L
Zhang
Jiangsu Key Laboratory of Biological Cancer Therapy, Xuzhou Medical College, Xuzhou 221002, PR China.
Qing
Q
Zhang
Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China.
Yu
Y
Yang
Key Laboratory of Bioresources and Ecoenvironment (Ministry of Education), College of Life Sciences, Sichuan University, Chengdu, PR China. Electronic address: wuchuanfangsichuan@gmail.com.
Chuanfang
C
Wu
D001483:Base Sequence; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D017931:DNA Primers; D006801:Humans; D008175:Lung Neoplasms / Q000235:genetics / Q000473:pathology*; D016133:Polymerase Chain Reaction; D012334:RNA, Neoplasm / Q000378:metabolism*
D017931:DNA Primers; D012334:RNA, Neoplasm
Alternative splicing; Apoptosis; Cell proliferation; RBM5; RNA binding; RNA recognition motif