Cold-inducible RNA-binding protein (Cirp) interacts with Dyrk1b/Mirk and promotes proliferation of immature male germ cells in mice

Abstract

Cold-inducible RNA-binding protein (Cirp) was the first cold-shock protein identified in mammals. It is structurally quite different from bacterial cold-shock proteins and is induced in response to mild, but not severe, hypothermia. To clarify the physiological function of Cirp in vivo, we produced cirp -knockout mice. They showed neither gross abnormality nor defect in fertility, but the number of undifferentiated spermatogonia was significantly reduced and the recovery of spermatogenesis was delayed after treatment with a cytotoxic agent, busulfan. Cirp accelerated cell-cycle progression from G0 to G1 as well as from G1 to S phase in cultured mouse embryonic fibroblasts. Cirp directly bound to dual-specificity tyrosine-phosphorylation–regulated kinase 1B (Dyrk1b, also called Mirk) and inhibited its binding to p27, resulting in decreased phosphorylation and destabilization of p27. Cirp did not affect binding of Dyrk1b to cyclin D1 but inhibited phosphorylation of cyclin D1 by Dyrk1b, resulting in cyclin D1 stabilization. In the spermatogonial cell line GC-1spg, suppression of Cirp expression increased the protein level of p27, decreased that of cyclin D1, and decreased the growth rate, which depended on Dyrk1b. Consistent changes in the protein levels of p27 and cyclin D1 as well as the percentage of cells in G0 phase were observed in undifferentiated spermatogonia of cirp -knockout mice. In undifferentiated spermatogonia of wild-type mice, Cirp and Dyrk1b colocalized in the nucleus. Thus, our study demonstrates that Cirp functions to fine-tune the proliferation of undifferentiated spermatogonia by interacting with Dyrk1b.

A Novel Candidate Gene for Temperature-Dependent Sex Determination in the Common Snapping Turtle

“…In Xenopus, CIRBP displays nucleocytoplasmic shuttling and has distinct roles in each cellular compartment (Aoki et al 2002). Nuclear CIRBP is associated with cell growth and differentiation (Lleonart 2010;Emmanuel et al 2011;Masuda et al 2012). In response to various environmental stressors, CIRBP moves from the nucleus to the cytoplasm where it associates with stress granules to regulate RNA metabolism (Yang and Carrier 2001;De Leeuw et al 2007).…”

Tumor Necrosis Factor and Transforming Growth Factor β Regulate Clock Genes by Controlling the Expression of the Cold Inducible RNA-binding Protein (CIRBP)

“…Genes-Because we found that siRNA against Cirbp sensitizes the cells to the effect of TNF to suppress Dbp mRNA, we analyzed the expression of clock genes in (MEFs), which were established from mice with an inactivation of the Cirbp gene (Cirbp Ϫ/Ϫ MEFs) (27). Compared with WT MEFs, the effect of TNF to lower the expression of clock genes was found to be more pronounced in Cirbp Ϫ/Ϫ MEFs (Fig.…”

“…Subsequently blotting on a PVDF membrane was performed in a full wet tank blot. Membranes were incubated with a CIRBP rabbit polyclonal antibody recognizing the C terminus of mouse CIRBP (27). As secondary antibody an HRP-conjugated goat anti-rabbit (ab79051; Abcam) was used and incubated for 1 h. As a loading control an antibody to the mouse nuclear matrix protein p84 was used (1 h, ab487).…”

Stress Response Protein Cirp Links Inflammation and Tumorigenesis in Colitis-Associated Cancer

“…The generation of Cirp À/À mice has been described previously (28 Isolation of lamina propria cells was performed as described previously (29). The isolated cells were sorted using immunomagnetic beads coated with monoclonal antibodies against CD11b (MACS Beads, Miltenyi Biotec) with the help of a separation column and a magnetic separator from the same company in accordance with the manufacturer's recommendations for isolating murine macrophages.…”

“…The following antibodies were used: anti-actin and anti-DCAMLK1 (Dclk1) from Sigma-Aldrich; anti-Bcl-2, anti-phospho-IkBa, antiIkBa, anti-phospho-ERK, anti-ERK, anti-Sox2, anti-E-cadherin, anti-PCNA from Cell Signaling; and anti-F4/80 from eBioscience. Generation of anti-Cirp polyclonal antibody was previously described (28). Immunohistochemistry was performed using ImmPRESS reagents (Vector Laboratory) according to the manufacturer's recommendations.…”