Anti-CAPG PAb

Background: Chromosome conformation capture (3C) is a powerful and widely used technique for detecting the physical interactions between chromatin regions in vivo. The principle of 3C is to convert physical chromatin interactions into specific DNA ligation products, which are then detected by quantitative polymerase chain reaction (qPCR). However, 3C-qPCR assays are often complicated by the necessity of normalization controls to correct for amplification biases. In addition, qPCR is often limited to a certain cycle number, making it difficult to detect fragment ligations with low frequency. Recently, digital PCR (dPCR) technology has become available, which allows for highly sensitive nucleic acid quantification. Main advantage of dPCR is its high precision of absolute nucleic acid quantification without requirement of normalization controls. Results: To demonstrate the utility of dPCR in quantifying chromatin interactions, we examined two prostate cancer risk loci at 8q24 and 2p11.2 for their interaction target genes MYC and CAPG in LNCaP cell line. We designed anchor and testing primers at known regulatory element fragments and target gene regions, respectively. dPCR results showed that interaction frequency between the regulatory element and MYC gene promoter was 0.7 (95% CI 0.401-10) copies per 1000 genome copies while other regions showed relatively low ligation frequencies. The dPCR results also showed that the ligation frequencies between the regulatory element and two EcoRI fragments containing CAPG gene promoter were 1.9 copies (95% CI 1.41-2.47) and 1.3 copies per 1000 genome copies (95% CI 0.76-1.92), respectively, while the interaction signals were reduced on either side of the promoter region of CAPG gene. Additionally, we observed comparable results from 3C-dPCR and 3C-qPCR at 2p11.2 in another cell line (DU145). Conclusions: Compared to traditional 3C-qPCR, our results show that 3C-dPCR is much simpler and more sensitive to detect weak chromatin interactions. It may eliminate multiple and complex normalization controls and provide accurate calculation of proximity-based fragment ligation frequency. Therefore, we recommend 3C-dPCR as a preferred method for sensitive detection of low frequency chromatin interactions.

Research on vascular endothelial cell ageing helps elucidate the pathogenesis of diseases associated with cell ageing. To investigate endothelial senescence, we used 2-DE coupled with MS to perform a proteomic analysis of: (i) peripheral blood mononuclear cells (PBMCs) from donors in their 20 s ('young') or 60 s ('old') and (ii) human dermal microvascular endothelial cells (HDMECs) treated with sera from young and old donors. Identified proteins could be classified into several functional categories: (i) cytoskeletal regulators: CapG and cofilin 1; (ii) stress response and signal pathway proteins: TXNDC5 and RSU-1; and (iii) apoptosis proteins: Annexin V. We confirmed by Western blot a decrease of RSU-1, CapG and TXNDC5 in PBMCs from old donors. RSU-1, which regulates signal transduction of the downstream Ras, showed decreased mRNA and protein levels in PBMCs from old donors and decreased mRNA levels in HDMECs treated with sera from old donors. In addition, Ras protein levels were increased in PBMCs from old donors. These data indicate that reduced RSU-1 might induce Ras expression, which subsequently could provoke Ras-induced senescence. In conclusion, our data suggest that blood components that exhibit age-related changes, such as alterations in cytoskeletal regulators and stress proteins, may be associated with endothelial cell ageing.