High Quality Content by WIKIPEDIA articles! Human YPEL3 is a recently discovered protein encoded by the YPEL3 gene, shown to have growth inhibitory effects in normal and tumor cell lines. One of five family members (YPEL1-5), YPEL3 was named in reference to its Drosophila melanogaster orthologue. Initially discovered in a gene expression profiling assay of p53 activated MCF7 cells, induction of YPEL3 has been shown to trigger permanent growth arrest or cellular senescence in certain human normal and tumor cell types.DNA methylation of a CpG island near the YPEL3 promoter as well as histone acetylation may represent possible epigenetic mechanisms leading to decreased gene expression in human tumors.