RNomics of Thermus themophilus HB8 by DNA microarray and next-generation sequencing.

By using the data obtained by the DNA microarray analysis for the intergenic regions applied to RNA samples extracted from Thermus thermophilus HB8, seven small non-coding RNAs, TtR-1 to TtR-7, were found to be expressed in the cells growing in rich and/or minimal media. By analysing the time course of the expression for the cell growth in combination with the sequence comparison to the known RNAs, two RNAs, TtR-1 and TtR-2, are suggested to be riboswitches. The existence of the seven RNAs and the exact sequence and length, ranging 77-284 nt, were confirmed by the next-generation sequencing. By the combination of these two high-throughput techniques, our understanding of RNAs in the cell will be increased significantly.

Brorin, a novel secreted bone morphogenetic protein antagonist, promotes neurogenesis in mouse neural precursor cells.

We identified a gene encoding a novel secreted protein in mice and humans and named it Brorin. Mouse Brorin consists of 324 amino acids with a putative secreted signal sequence at its amino terminus and two cysteine-rich domains in its core region. Positions of 10 cysteine residues in the domains of Brorin are similar to those in the cysteine-rich domains of members of the Chordin family. However, the amino acid sequence of Brorin is not significantly similar to that of any other member of the Chordin family, indicating that Brorin is a unique member of the family. Mouse Brorin protein produced in cultured cells was efficiently secreted into the culture medium. The protein inhibited the activity of bone morphogenetic protein 2 (BMP2) and BMP6 in mouse preosteoblastic MC3T3-E1 cells. Mouse Brorin was predominantly expressed in neural tissues in embryos and also predominantly expressed in the adult brain. In the brain, the expression was detected in neurons, but not glial cells. The neural tissue-specific expression profile of Brorin is quite distinct from that of any other member of the Chordin family. Brorin protein promoted neurogenesis, but not astrogenesis, in mouse neural precursor cells. The present findings indicate that Brorin is a novel secreted BMP antagonist that potentially plays roles in neural development and functions.

Role of Fgf10 in cell proliferation in white adipose tissue.

The development of white adipose tissue (WAT) involves adipogenesis and cell proliferation. Although the adipogenesis has been well studied, the cell proliferation has not. Therefore, we examined the mechanism of the proliferation by analyzing Fgf10(-/-) mouse embryonic WAT, in which adipogenesis and proliferation were severely impaired. D-type cyclin expression and retinoblastoma family protein phosphorylation essential for cell proliferation were examined in WAT. Both cyclin D2 expression and p130 phosphorylation were impaired in the Fgf10(-/-) WAT. In mouse embryonic fibroblasts, Fgf10 stimulated cyclin D2 expression and p130 phosphorylation, which were inhibited by an inhibitor of the Ras/MAPK pathway. These results suggest that Fgf10 stimulates cell proliferation in WAT through the Ras/MAPK pathway followed by the cyclin D2-dependent phosphorylation of p130. In contrast, expression but not phosphorylation of pRb was impaired in the Fgf10(-/-) WAT. As pRb is essential for adipogenesis, Fgf10 might play a role in adipogenesis by inducing its expression.