Report on IL-10 gene polymorphism at position -819 for major depression and schizophrenia in Korean population

The present study was carried out to examine the relationship of interleukin (IL)-10 gene polymorphism at position -819 for major depression and schizophrenia in the Korean population. DNA was extracted from 92 Korean patients with major depression, 141 Korean patients with schizophrenia, and 146 ethnically matched controls. DNA was amplified by a polymerase chain reaction-based method and digested by MaeIII, and the restriction fragment length polymorphism of two alleles, IL-10*C and IL-10*T, were assessed. There were no significant differences in genotype frequencies of IL-10*T/T, IL-10*T/C, and IL-10*C/C as well as allelic frequencies of IL-10*T and IL-10*C between patients with major depression and controls in the Korean population. Comparison of genotype and allelic frequencies of IL-10 gene between patients with schizophrenia and controls were also not significant. The present study suggests that IL-10 gene polymorphism at position -819 does not confer susceptibility to major depression and schizophrenia, at least in the Korean population. Further systematic studies including various clinical variables would be required.

Polymorphism of CTLA-4 gene for major depression in the Korean population

This study was carried out to verify the relationship between major depression and cytotoxic T lymphocyte antigen-4 (CTLA-4), which is related to immunological function such as T-cell regulation. Among the Korean patients diagnosed with major depression according to DSM-IV, 77 patients without neurological illness, hormonal disorder, or comorbid mental illness were selected. The stored data on 149 normal Koreans from the Catholic Hemopoietic Stem Cell Bank of Korea, were used as a control group. The data of the Korean control group were compared with those of the studies of different ethnic groups. DNA was extracted from whole blood using proteinase K and the exon 1 region of CTLA-4 gene was amplified by polymerase chain reaction. Gene typing was performed using single strand conformation polymorphism. The results were assessed. There were significant differences in frequencies of CTLA-4 allele (chi2 = 56.472, d.f. = 1, P = 0.001) and genotype (chi2 = 46.132, d.f. = 2, P = 0.001) between the Korean population and the Caucasian population. However, we could not find any differences between the Korean and the Japanese population. There were no significant differences in genotype frequencies of CTLA-4*G/G, CTLA-4*G/A, and CTLA-4*A/A between the patients with major depression and the control group in the Korean population (48.1% vs. 46.3%, 41.6% vs 39.6%, 10.3% vs. 14.1%, respectively). There were no significant differences in allelic frequencies of CTLA-4*G and CTLA-4*A between the patients with major depression and the control group in the Korean population (68.8% vs. 66.1%, 31.2% vs. 33.9%, respectively). Although the present study produced negative results for the association of exon 1 polymorphism of CTLA-4 gene with major depression in the Korean population, further systematic research, including diverse clinical variables, would be necessary.

Cloning and characterization of the 5'-flanking region for the mouse phospholipase C-delta1 gene

To date, little is known about the molecular mechanisms controlling the regulation of phospholipase C-delta1 (PLC-delta1) gene expression. To understand the mechanisms responsible for the regulation of PLC-delta1 gene expression, the 5'-flanking region of the mouse PLC-delta1 gene was isolated from a mouse genomic DNA library. Primer extension analysis revealed that there is a single transcriptional start site located at 127 bases upstream from the translation start codon in the mouse PLC-delta1 gene. DNA sequence analysis showed that the sequence around the transcriptional start site is very GC-rich and has no TATA or CAAT boxes. Transient expression of a luciferase reporter gene under the control of serially deleted 5'-flanking sequences revealed that the 160-base-pair region from -622 to -462 upstream of the transcriptional start site includes a positive cis-acting element(s) for the efficient expression of the PLC-delta1 gene. Gel retardation analysis suggests that multiple transcription factors bind to separate sites on the promoter region. Based on these results, our study suggests that the minimal essential region located at -622 to +70 is fully sufficient to confer high-level transcriptional activity and contains high-affinity binding elements for multiple transcription factors.