Fas and Fas ligand (FasL) polymorphisms in the promoter regions influence transcriptional activities. The interaction of these two genes plays a crucial role in apoptotic cell death regulation. They have been associated with esophageal, lung, uterine cervical, and urinary bladder cancers in human. We performed a case-control study to investigate the association between Fas and FasL polymorphisms and acute myeloid leukemia (AML) risk. Fas−1377G>A (rs2234767), −670T>C (rs1800682), and FasL−844T>C (rs763110) polymorphisms in 592 AML patients and 858 healthy controls were genotyped and tested for associations between polymorphisms and AML risk. There were no significant differences in genotypic and haplotypic distributions and gene-gene interaction between patients and controls in the overall analysis (p>0.05). These results suggested that polymorphisms of Fas and FasL genes were not associated with AML risk in the Korean population.

The P-element-induced wimpy testis (PIWI) protein, which associates with small non-coding RNAs, is responsible for maintaining the integrity of germ cells and stem cells. Thus, transcriptional regulation of PIWI is critical for its effective functional modulation. In this study, we identified the promoter region of the PIWI homolog in chicken (CIWI), and investigated the transcriptional regulatory elements that control expression of CIWI in chicken primordial germ cells (PGCs). We constructed a vector that included the enhanced green fluorescent protein (eGFP) gene controlled by the 4-kb CIWI promoter. The vector was expressed in chicken PGCs, but not in chicken embryonic fibroblasts. Based on promoter deletion and fragmentation assays, we found that a 252-bp fragment of the CIWI promoter (-577 to -326 bp) was crucial for CIWI expression in PGCs. A CCAAT transcriptional regulatory element (-498 to -494 bp) was detected in the proximal region from the transcription initiation site of CIWI, and mutational analysis confirmed that this element regulates transcriptional initiation in chicken PGCs. Interestingly, the regions flanking the CCAAT element, which are positioned differently in HIWI (human), Miwi (mouse), and CIWI orthologs, were highly conserved. In addition, we predicted that specificity protein 1 (SP1) motifs modulate the transcriptional initiation of CIWI by binding to the 5'-flanking regions of the CCAAT box. Overall, 252 bp of the CIWI promoter possessing the transcriptional regulatory element CCAAT is crucial for regulating CIWI gene expression in chicken PGCs. This promoter may be applicable for the regulation of CIWI expression during germ-cell development.