Search

The present study investigated the effects of 5-azacytidine (5-azaC) on the expression level of the human runt-related transcription factor 3 (RUNX3) gene and the biological behavior of esophageal carcinoma Ecal09 cells. The effect of the demethylation reagent 5-azaC on the viability of Ecal09 cells was detected by the MTT assay, which demonstrated that 5-azaC inhibited the viability of Ecal09 cells in a time- and dose-dependent manner. Although demethylation of other genes may occur following treatment with 5-azaC, we focused on the RUNX3 gene. When treated with 5-azaC at hypoxic levels, the expression of RUNX3 increased and the methylation degree of the RUNX3 gene was decreased significantly in Ecal09 cells. 5-azaC at 50 jaM demonstrated the highest RUNX3-induction activity, inducing RUNX3 mRNA and protein expression, and decreasing the degree of methylation of the RUNX3 gene. Methylation specific PCR indicated that 5-azaC induced RUNX3 expression through demethylation. The abilities of migration and invasion of Ecal09 cells were inhibited by 5-azaC. The growth of Ecal09 cells treated with 5-azaC in vivo was detected by a tumorigenesis experiment. 5-azaC inhibited the growth of Ecal09 xenografts in nude mice. Taken together, our findings demonstrated that the RUNX3 gene is hypermethylated in Ecal09 cells and that 5-azaC induces the expression of the RUNX3 gene by demethylation, which inhibits the proliferation, migration and invasion of Ecal09 cells. [ABSTRACT FROM AUTHOR]

Rice yield and heading date are two distinct traits controlled by quantitative trait loci (QTLs). The dissection of molecular mechanisms underlying rice yield traits is important for developing high-yielding rice varieties. Here, we report the cloning and characterization of Ghd8, a major QTL with pleiotropic effects on grain yield, heading date, and plant height. Two sets of near isogenic line populations were developed for the cloning of Ghd8. Ghd8 was narrowed down to a 20-kb region containing two putative genes, of which one encodes the OsHAP3 subunit of a CCAAT-box binding protein (HAP complex); this gene was regarded as the Ghd8 candidate. A complementary test confirmed the identity and pleiotropic effects of the gene; interestingly, the genetic effect of Ghd8 was dependent on its genetic background. By regulating Ehd1, RFT1, and Hd3a, Ghd8 delayed flowering under long-day conditions, but promoted flowering under short-day conditions. Ghd8 up-regulated MOC1, a key gene controlling tillering and branching; this increased the number of tillers, primary and secondary branches, thus producing 50% more grains per plant. The ectopic expression of Ghd8 in Arabidopsis caused early flowering by 10 d—a situation similar to the one observed by its homolog AtHAP3b, when compared to wild-type under long-day conditions; these findings indicate the conserved function of Ghd8 and AtHAP3b in flowering in Arabidopsis. Our results demonstrated the important roles of Ghd8 in rice yield formation and flowering, as well as its opposite functions in flowering between rice and Arabidopsis under long-day conditions. [ABSTRACT FROM PUBLISHER]