c-Maf plays a crucial role for the definitive erythropoiesis that accompanies erythroblastic island formation in the fetal liver.

c-Maf is one of the large Maf (musculoaponeurotic fibrosarcoma) transcription factors that belong to the activated protein-1 super family of basic leucine zipper proteins. Despite its overexpression in hematologic malignancies, the physiologic roles c-Maf plays in normal hematopoiesis have been largely unexplored. On a C57BL/6J background, c-Maf(-/-) embryos succumbed from severe erythropenia between embryonic day (E) 15 and E18. Flow cytometric analysis of fetal liver cells showed that the mature erythroid compartments were significantly reduced in c-Maf(-/-) embryos compared with c-Maf(+/+) littermates. Interestingly, the CFU assay indicated there was no significant difference between c-Maf(+/+) and c-Maf(-/-) fetal liver cells in erythroid colony counts. This result indicated that impaired definitive erythropoiesis in c-Maf(-/-) embryos is because of a non-cell-autonomous effect, suggesting a defective erythropoietic microenvironment in the fetal liver. As expected, the number of erythroblasts surrounding the macrophages in erythroblastic islands was significantly reduced in c-Maf(-/-) embryos. Moreover, decreased expression of VCAM-1 was observed in c-Maf(-/-) fetal liver macrophages. In conclusion, these results strongly suggest that c-Maf is crucial for definitive erythropoiesis in fetal liver, playing an important role in macrophages that constitute erythroblastic islands.

An objective estimation of the removability of three home reliners.

The purpose of this study was to investigate methods for evaluating objectively the removability of three commercially available home reliners (Cushion Correct, Tafugurippu Pink A and Liodent Pink). After immersing each of the reliners in distilled water at 37ºC for 24 h, we compared their removability using the peel test with a finger, which was evaluated based on a visual analogue scale and the percentage of the residual area. An experimental rake-up test was also undertaken to quantify removability, evaluated based on the total amount of work required to remove it. The Tafugurippu Pink A product was easier to remove with a finger than the other two home reliner products, and required the least total amount of work to be removed in the experimental rake-up test. Furthermore, the rake-up test performed could possibly be used for objective evaluation of the removability of home reliner.

c-Maf is essential for the F4/80 expression in macrophages in vivo.

c-Maf, which is one of the large Maf transcription factors, can bind to Maf recognition element (MARE) and activates transcription of target genes. Although c-Maf is expressed in macrophages and directly regulates the expression of interleukin-10, detailed information regarding its function in the null mutant phenotype of tissue macrophages remain unknown. In this study, we demonstrated that c-Maf is specifically expressed in the F4/80 positive fetal liver and adult macrophages. The expression of F4/80, which is a tissue macrophage-specific seven trans-membrane receptor, was dramatically suppressed in the c-Maf-deficient macrophage, whereas the expression of Mac-1 was not affected, suggesting that c-Maf is not necessary for the lineage commitment of macrophages. Luciferase reporter and EMSA showed that c-Maf directly regulates the expression of F4/80 by interacting with the half-MARE site of the F4/80 promoter. These results suggest that c-Maf is required for the F4/80 expression in macrophages in vivo.