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. Author manuscript; available in PMC: 2009 Jun 8.
Published in final edited form as: Oncogene. 2009 Jan 26;28(12):1561–1568. doi: 10.1038/onc.2008.497

Figure 4. Ha-Ras and developmental regulation of SIM2s by C/EBPβ.

Figure 4

(a) C/EBPβ isoform expression in Ha-Ras-MCF10A and control (pLPCX) MCF10A cells. Western blot analysis of Ha-Ras-MCF10A and control cell shows an Ha-Ras-dependent increase in C/EBPβ-LIP isoform expression (C/EBPβ antibody; Santa Cruz). (b) C/EBPβ-LIP-mediated suppression of SIM2s expression in MCF10A cells. Western blot for SIM2s (Chemicon) in MCF10A cells stably transduced with pBABE (vector control) or the indicated C/EBPβ isoforms shows a significant reduction of SIM2s protein levels in the LIP-transduced cells. Vectors (pBABEpuro or pEFIRESpuro backbones) containing human and mouse C/EBPβ isoforms were graciously provided by C Zahnow. (c, d) SIM2s expression in wild-type and C/ebpβ−/− mammary glands. Elevated SIM2s gene expression and protein levels in C/ebpβ−/− mammary glands as determined by real-time RT-PCR and immunohistochemistry, respectively (Laffin et al., 2008). (e) SIM2s expression in a C/ebpβ−/− mouse mammary epithelial cell line. Similar to the C/ebpβ−/− mammary glands, SIM2s levels are increased in mouse mammary epithelial cells derived from C/ebpβ−/− mammary glands (Lamb et al., 2003) by real-time RT-PCR as compared to normal HC11 cells (*P≤0.001). (f, g) Reestablishment of mouse C/ebpβ isoforms in the C/ebpβ−/− cells as determined by western blot analysis correlates with a decrease in SIM2s mRNA levels (*P≤0.001). Data are expressed as the mean±s.e. for three plates per condition.