RINF expression and subcellular localization in NB4 cells and other myeloid cell lines and tissues. (A) Relative expression of RINF mRNA levels (measured by quantitative RT-PCR) during 1 μM ATRA treatment of NB4 cells. (B) Expression of RINF protein in total extracts from NB4 cells treated or not treated with 1 μM ATRA. RINF was detected with our customized polyclonal rabbit antibody (see “Methods”) that detects a specific band at 33 kDa. Actin was used as a loading control. (C) Expression of RINF protein in nuclear and cytosolic fractions of NB4 cells treated or not treated with 1 μM ATRA. RINF was detected with the polyclonal antibody. In this experiment, PARP and actin were used as controls to evaluate quality, purity, and loading of the nuclear and cytosolic extracts. (D) FLAG-tagged RINF (green; Alexa Fluor 488–conjugated anti-FLAG monoclonal antibody) localizes in the nucleus (stained in blue with DAPI) of MCF7 cells analyzed by confocal and differential interference contrast (DIC) microscopy. Scale bar, 10 μm. (E) RINF mRNA expression in various myeloid cell lines measured by quantitative RT-PCR with or without ATRA at 4 hours of treatment (see “Methods”). Expression of RINF protein in various myeloid cell lines (F) treated or not treated with 1 μM ATRA during 4 hours and in various human tissues (G). The same amounts of protein (determined with bicinchoninic acid [BCA] assay test) were loaded for each of the myeloid cell line (20 μg) and human tissue extracts (65 μg; see “Methods”). Actin was used as a loading control.