Novel DNase I hypersensitive sites in the 3'-flanking region of the human c-myc gene

Association of CHI3L1 gene variants with YKL-40 levels and hypertension incidence: A population-based nested case-control study in China

YKL‐40 was reported to be associated with the risk of hypertension. Whether the variants of CHI3L1 gene were associated with both YKL‐40 levels and hypertension needs to be further elucidated. In a 1:1 matched case‐control study of 507 pairs with available YKL‐40 levels and DNA samples nested in a prospective cohort of Chinese subjects, the 15 tag single nucleotide polymorphisms (SNPs) of CHI3L1 gene were genotyped. The levels of YKL‐40 among different genotypes of each SNP were compared after false discovery rate adjustment. Multivariable conditional logistic regression analyses were used to explore the association between the genotypes and the risk of hypertension. Subjects with the genetic variants for rs10399931, rs1538372, rs2071580, rs2297839 and rs4950928 had lower YKL‐40 levels. The genetic variant for rs10399805 was associated with higher YKL‐40 level. Subjects with the genotype of GA/AA of rs10399805 had a 1.34‐fold risk of hypertension compared with those with GG genotype in the total population (P = .05). Subjects with heterozygote/rare homozygote genotype of rs4950928 and rs2297839 both had a significantly lower risk of hypertension compared with those with major homozygote genotype among men. The ORs (95% CIs) were 0.46 (0.23‐0.89) and 0.49 (0.26‐0.91), respectively. The above three SNPs could significantly improve the accuracy of risk prediction for hypertension based on the conventional factors. The genotypes of rs10399805, rs4950928 and rs2297839 may hopefully become stable biomarkers for predicting the risk of hypertension.

Potentially Functional Polymorphisms in POU5F1 Gene Are Associated with the Risk of Lung Cancer in Han Chinese

POU5F1 is a key regulator of self-renewal and differentiation in embryonic stem cells and may be associated with initiation, promotion, and progression in cancer. We hypothesized that functional polymorphisms in POU5F1 may play an important role in modifying the lung cancer risk. To test this hypothesis, we conducted a case-control study to explore the association between 17 potentially functional SNPs in POU5F1 gene and the lung cancer risk in 1,341 incident lung cancer cases and 1,982 healthy controls in a Chinese population. We found that variant alleles of rs887468 and rs3130457 were significantly associated with increased risk of lung cancer after multiple comparison (OR = 1.29, 95% CI: 1.11-1.51, P fdr = 0.017 for rs887468; OR = 1.29, 95% CI: 1.10-1.51, P fdr = 0.034 for rs3130457, resp.). In addition, we detected a significant interaction between rs887468 genotypes and smoking status on lung cancer risk (P = 0.017). Combined analysis of these 2 SNPs showed a significant allele-dosage association between the number of risk alleles and increased risk of lung cancer (P trend < 0.001). These findings indicate that potentially functional polymorphisms in POU5F1 gene may contribute to lung cancer susceptibility in a Chinese population.

Regulation of c-myc transcription by interleukin-2 (IL-2). Identification of a novel IL-2 response element interacting with STAT-4

Regulation of c-myc expression is known to occur at the level of transcription initiation. However, the participating promoter elements and their cognate binding proteins have not been fully characterized. c-myc transcription can be stimulated by a number of cytokines including interleukin-2 (IL-2). We have identified a novel IL-2-responsive element, located in the 5'-flanking region of the c-myc gene, between nucleotides -1406 and -1387 (relative to the P2 promoter). This element belongs to the family of interferon-gamma activation site-like responsive elements and has the core sequence TTCCAATAA. We confirmed that IL-2-mediated signaling involves activation by phosphorylation of Jak2 tyrosine kinase and subsequently STAT4. The transcription factor STAT4 binds the TTCCAATAA motif within this responsive element and, therefore, is probably involved in enhancing c-myc transcription upon IL-2 stimulation. Our results propose participation of Jak2 and STAT4 in IL-2-induced up-regulation of c-myc.

Tissue transglutaminase: an enzyme with a split personality

Tissue transglutaminase (tTG) belongs to the family of transglutaminase enzymes that catalyze the posttranslational modification of proteins via Ca(2+)-dependent cross-linking reactions. The catalytic action of tTG results in the formation of an isopeptide bond that is of great physiological significance since it is highly resistant to proteolysis and denaturants. Although tTG-mediated cross-linking reactions have been implicated to play a role in diverse biological processes, the precise physiological function of the enzyme remains unclear. Recent data, however, suggest that the protein polymers resulting from tTG-catalyzed reactions may play a role in commitment of cells to undergo apoptosis. On the same token, tTG-mediated formation of insoluble protein aggregates may underlie the markers of numerous pathological conditions, such as the senile plaques in Alzheimer's disease and the Lewy bodies in Parkinson's disease. In addition to catalyzing Ca(2+)-dependent cross-linking reactions, tTG can also bind and hydrolyze guanosine triphosphate and adenosine triphosphate. By virtue of this ability, tTG has been identified as a novel G-protein that interacts and activates phospholipase C following stimulation of the alpha-adrenergic receptor. The ability of tTG to mediate signal transduction may contribute to its involvement in the regulation of cell cycle progression. The following review summarizes the important features of this multifunctional enzyme that have emerged as a result of recent work from different laboratories.