Regulated expression of a transgene introduced on an oriP/EBNA-1 PAC shuttle vector into human cells

<p>Abstract</p> <p>Background</p> <p>Sequencing of the human genome has led to most genes being available in BAC or PAC vectors. However, limited functional information has been assigned to most of these genes. Techniques for the manipulation and transfer of complete functional units on large DNA fragments into human cells are crucial for the analysis of complete genes in their natural genomic context. One limitation of the functional studies using these vectors is the low transfection frequency.</p> <p>Results</p> <p>We have constructed a shuttle vector, pPAC7, which contains both the <it>EBNA-1 </it>gene and <it>ori</it>P from the Epstein-Barr virus allowing stable maintenance of PAC clones in the nucleus of human cells. The pPAC7 vector also contains the <it>EGFP </it>reporter gene, which allows direct monitoring of the presence of PAC constructs in transfected cells, and the <it>Bsr</it>-cassette that allows highly efficient and rapid selection in mammalian cells by use of blasticidin. Positive selection for recombinant PAC clones is obtained in pPAC7 because the cloning sites are located within the SacBII gene. We show regulated expression of the <it>CDH3 </it>gene carried as a 132 kb genomic insert cloned into pPAC7, demonstrating that the pPAC7 vector can be used for functional studies of genes in their natural genomic context. Furthermore, the results from the transfection of a range of pPAC7 based constructs into two human cell lines suggest that the transfection efficiencies are not only dependent on construct size.</p> <p>Conclusion</p> <p>The shuttle vector pPAC7 can be used to transfer large genomic constructs into human cells. The genes transferred could potentially contain all long-range regulatory elements, including their endogenous regulatory promoters. Introduction of complete genes in PACs into human cells would potentially allow complementation assays to identify or verify the function of genes affecting cellular phenotypes.</p

Endoglin pathway genetic variation in preeclampsia: A validation study in Norwegian and Latina cohorts

Objective: The purpose of this study was to validate our previous genetic association findings related to the endoglin (ENG) pathway from an American Caucasian preeclampsia cohort in independent preeclampsia cohorts. We also sought to explore the ENG pathway for new genetic associations in these independent cohorts. Study design: We used a tagging single nucleotide (tSNP) approach to assess genetic variability across five ENG pathway genes (ENG, TGFβ1, TGFβR1, ALK1, and TGFβR2) in a Caucasian cohort from Norway (n = 77 preeclampsia cases & n = 63 normotensive controls) and a White Hispanic cohort from Southern California (n = 69 preeclampsia cases & n = 106 normotensive controls). Main outcome measures: Univariate analyses (Chi Square, Fisher’s Exact) and multivariate logistic regression were conducted to evaluate the association between tSNP genotype distributions and pregnancy outcome in each cohort. Logistic regression models were adjusted for maternal age at delivery, infant sex, parity, smoking during pregnancy, and pre-pregnancy BMI. Results: Although we were unable to replicate our previous SNP-specific findings (ENG rs11792480, rs10121110; TGFβR2 rs6550005; p’s > 0.05), we found that genetic variation in TGFβR1[ALK5] (rs6478974) and TGFβR2 (rs11129420, rs6802220, rs1155708, rs3773640, rs3773663) was significantly associated with preeclampsia in the Norwegian cohort and genetic variation in ALK1 (rs706819) and TGFβR2 (rs9843942) was significantly associated with preeclampsia in the Latina cohort. Conclusion: Overall, our results provide further support for the involvement and investigation of the endoglin pathway in preeclampsia

The combination of maternal KIR-B and fetal HLA-C2 is associated with decidua basalis acute atherosis in pregnancies with preeclampsia

Acute atherosis is an arterial lesion most often occurring in pregnancies complicated by preeclampsia, a hypertensive pregnancy disorder. Acute atherosis predominates in the maternal spiral arteries in the decidua basalis layer of the pregnant uterus. This layer forms the fetal-maternal immunological interface, where fetal extravillous trophoblasts interact with maternal immune cells to promote decidual spiral artery remodeling and maternal immune tolerance towards the fetus. Of the classical polymorphic class I HLAs, extravillous trophoblasts express only HLA-C. HLA-C is a ligand for killer immunoglobulin-like receptors (KIR) on NK- and T-cells. Genetic combinations of fetal HLA-C and maternal KIRs affect pregnancy outcome. However, the role of HLA and KIR genes in acute atherosis is unknown. We hypothesized that specific genetic combinations of fetal HLA and maternal KIR are associated with the presence of acute atherosis lesions in the decidua basalis. We genotyped HLA class-I and II loci in paired fetal and maternal DNA samples from 166 pregnancies (83 preeclamptics, 83 controls). Acute atherosis was identified in 38 of these. Maternal KIR-loci were also genotyped. We found that the combination of maternal KIR-B haplotype and fetal HLA-C2 was significantly associated with acute atherosis in preeclampsia. In preeclamptic pregnancies with acute atherosis, 60% had this combination, compared to 24.5% in those without acute atherosis (p = 0.001). We suggest that interactions between fetal HLA-C2 and activating KIRs on maternal decidual NK-cells or T-cells may contribute to the formation of acute atherosis by promoting local decidual vascular inflammation