The Long Terminal Repeat of Jaagsiekte Sheep Retrovirus Is Preferentially Active in Differentiated Epithelial Cells of the Lungs

• DOI: 10.1128/jvi.74.13.5776-5787.2000
• Publication Date: 2002-07-27T10:06:23Z
• Authors: Massimo Palmarini; Shoibal Datta; Reza Omid; Claudio Murgia; Hung Fan
• Keywords: Heterologous; 3T3 cells; Cell type

ABSTRACT Jaagsiekte sheep retrovirus (JSRV) is the etiologic agent of a contagious bronchioloalveolar carcinoma known as pulmonary adenomatosis (SPA; ovine carcinoma). JSRV unique among retroviruses because it transforms alveolar type II cells and nonciliated bronchiolar (Clara cells) lungs; these are where specifically expressed in both naturally experimentally SPA-affected sheep. In this study, we investigated cell specificity expression. By transient-transfection assays 23 different lines with reporter plasmid driven by long terminal repeat (LTR), pJS21-luc, found that LTR preferentially active derived from pneumocytes Clara (MLE-15 mtCC1-2 mouse lines). Reporter using progressive 5′ deletions pJS21-luc allowed us to establish enhancers able activate proximal promoter MLE-15 cells, but they have very low activity other lineages (e.g., NIH 3T3). The heterologous promoters 3T3 although optimal achieved only homologous promoter. Thus, cell-specific appears result an interaction between enhancer elements elements. mutation analysis, established upstream NF-κB-like element be responsible for approximately 50% transcriptional cells. Electrophoretic mobility shift showed evidence factor(s) binds sequence. Antibody supershift experiments indicated not related NF-κB component p50 or p52. This factor also appeared present do support high level Finally 21 contains putative binding motifs transcription factors such hepatocyte nuclear 3 (HNF-3) involved lung-specific gene Cotransfection demonstrated exogenous HNF-3 enhance expression which normally show minimal LTR.