Use of chromatin immunoprecipitation (ChIP) to detect transcription factor binding to highly homologous promoters in chromatin isolated from unstimulated and activated primary human B cells

The Chromatin Immunoprecipiation (ChIP) provides a powerful technique for identifying the in vivo association of transcription factors with regulatory elements. However, obtaining meaningful information for promoter interactions is extremely challenging when the promoter is a member of a class of highly homologous elements. Use of PCR primers with small numbers of mutations can limit cross-hybridization with non-targeted sequences and distinguish a pattern of binding for factors with the regulatory element of interest. In this report, we demonstrate the selective in vivo association of NF-κB, p300 and CREB with the human Iγ1 promoter located in the intronic region upstream of the Cγ1 exons in the immunoglobulin heavy chain locus. These methods have the ability to extend ChIP analysis to promoters with a high degree of homology

Expression and prognostic significance of THBS1, Cyr61 and CTGF in esophageal squamous cell carcinoma

<p>Abstract</p> <p>Background</p> <p>Thrombospondin1 (THBS1), cystene-rich protein 61 (Cyr61) and connective tissue growth factor (CTGF) are all involved in the transforming growth factor-beta (TGF-β) signal pathway, which plays an important role in the tumorigenesis. The purpose of this study is to explore the expression and prognostic significance of these proteins in esophageal squamous cell carcinoma (ESCC).</p> <p>Methods</p> <p>We used immunohistochemistry and western blotting to examine the expression status of THBS1, Cyr61 and CTGF in ESCC. Correlations of THBS1, Cyr61 and CTGF over-expressions with various clinicopathologic factors were also determined by using the Chi-square test or Fisher's exact probability test. Survival analysis was assessed by the Kaplan-Meier analysis and the log-rank test. Relative risk was evaluated by the multivariate Cox proportional hazards model.</p> <p>Results</p> <p>THBS1, Cyr61 and CTGF were all over-expressed in ESCC. THBS1 over-expression was significantly associated with TNM stage (<it>P </it>= 0.029) and regional lymph node involvement (<it>P </it>= 0.026). Kaplan-Meier survival analysis showed that over-expression of THBS1, Cyr61 or CTGF was related to poor survival of ESCC patients (<it>P </it>= 0.042, <it>P </it>= 0.020, <it>P </it>= 0.018, respectively). Multivariate Cox analysis demonstrated that Cyr61 and CTGF were independent factors in prognosis of ESCC.</p> <p>Conclusion</p> <p>Cyr61, CTGF and THBS1 were all over-expressed in ESCC and might be new molecular markers to predict the prognosis of ESCC patients.</p

Mechanism of up-regulation of immunoglobulin A production in the intestine of mice unresponsive to lipopolysaccharide

The mechanisms by which immunoglobulin A (IgA) production up-regulates in the intestine of Toll-like receptor-4 (TLR4)-mutated mice were investigated. When TLR4-mutated, C3H/HeJ and BALB/lps(d) mice received oral administration of cholera toxin (CT), not only CT-specific IgA levels in the intestinal lavage but also the number of IgA-producing cells in intestinal lamina propria (iLP) significantly increased compared with those of the wild-type C3H/He and BALB/c mice. Interleukin (IL)-5-producing cells and CD86(+) cells in iLP also significantly increased in C3H/HeJ mice. The expression of major histocompatibility complex class II and CD86 on cells present in Peyer's patches (PPs) of C3H/HeJ mice was higher than those of C3H/He mice. In non-immunized C3H/HeJ mice, the expression of transforming growth factor-β (TGF-β) mRNA and the percentages of IL-10-producing cells in PPs but not in spleen increased when compared with those in C3H/He mice. The suppressor of cytokine signalling-1 (SOCS-1) was expressed in PPs of C3H/He mice but not C3H/HeJ mice. These results indicate that high IgA levels in the intestine of TLR4-mutated mice are due to up-regulation of TGF-β and IL-10 and the lack of regulation by SOCS-1