Obox4 regulates the expression of histone family genes and promotes differentiation of mouse embryonic stem cells

Obox genes are preferentially expressed in the ovary, testis and oocyte, and play important roles in many developmental processes. In this study, we report that Obox4 and Obox6 are expressed in mouse embryonic stem cells (mESCs) and that Obox4 regulates histone family gene expression in mESCs. Obox4 protein expressing mESCs formed colonies with a flattened and irregular morphology, and exhibited decreased expression levels of self-renewal related proteins, such as Oct4 and Sox2, as well as reduced alkaline phosphatase activity. The results of microarray analysis and siRNA mediated knockdown experiments suggest that Obox4 is an upstream regulator of the histone gene family.     

Testis-specific expression of a novel mouse defensin-like gene,Tdl

In order to isolate genes regulating sex differentiation of embryonic gonads, we have attempted to obtain genes specifically expressed in male embryonic gonads by means of subtractive hybridization screening, and we have cloned a novel mouse gene, Tdl. It potentially encodes a protein showing sequence homology to anti-microbial protein, beta-defensins. Tdl reveals structural features such as the six cysteine residues with invariant spacing, which are found in beta-defensins, but the overall amino acid similarity of Tdl to other members of the beta-defensin family is low. In addition, the Tdl gene shows genomic organization similar to that of other beta-defensin genes. We have found that Tdl is specifically expressed in Sertoli cell-lineage in seminiferous cords in embryonic testes, but not in embryonic ovaries after 12.5dpc when the sexual differentiation of gonads is initiated. Tdl is specifically expressed in gonads among adult tissues, and its expression persisted in Sertoli cells.     

Identification and gene expression profiling of the Pum1 and Pum2 members of the Pumilio family in the chicken

Members of the Pumilio (Pum) family of RNA-binding proteins act as translational repressors and are required for germ cell development and asymmetric division. We identified the chicken Pum1 and Pum2 genes and analyzed their expression patterns in various tissues. Comparative sequence analysis of the Pum1 and Pum2 proteins from the drosophila, chicken, mouse, and human revealed a high degree of evolutionary conservation in terms of the levels of homology of the peptide sequences and the structure of Pumilio homology domain (PUM-HD), C-terminal RNA-binding domain, with similar spacing between the adjacent Pum eight tandem repeats. In addition, phylogenetic patterns of pumilio family showed that Pum 1 and 2 of chicken are more closely related to those of mouse and human than other species and Pum1 is more conserved than Pum2. Using real-time RT-PCR, the expression levels of the Pum1 and Pum2 genes were found to be highest in hatched female gonads, and high-level expression of Pum2 was detected in 12-day and hatched gonads among the various chicken embryonic tissues tested. In adult tissues, the expression levels of Pum1 and Pum2 were expressed at higher levels in the testis and muscle than in any other tissue. The characteristics of the tissue-specific expression of Pum genes suggest that Pum1 and Pum2 have effects crucially in particular stage during development of chicken gonads depending on sexual maturation.