title: Immunoglobulin kappa gene expression after stable integration. I. Role of the intronic MAR and enhancer in plasmacytoma cells.
abstract: Rearranged MOPC41 immunoglobulin kappa gene constructs have been stably introduced into cultured S194 mouse plasmacytoma cells to investigate the effects of deleting the intronic enhancer and/or matrix association region (MAR) on gene expression. Intact single-copy kappa genes containing 1.5 kilobase pairs of upstream and 8.5 kilobase pairs of downstream flanking sequences exhibited sensitivity to chromosome position effects and were expressed at a mean level of 27% relative to the endogenous kappa gene expression or only 6% with respect to the MOPC41 kappa mRNA levels in the tumor. Deletion of the intronic MAR led to a 4-fold decrease in expression, while deletion of both the MAR and enhancer led to an 11-fold decline. These effects were dampened by preselecting for integration into a transcriptionally poised chromatin location as demonstrated by linkage to a selectable marker which lacked both a MAR and an enhancer. Significantly, we found that sequences downstream of the poly(A) addition site compensated 150-fold for deletion of the intronic enhancer.
authors.affiliation: Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
authors.forename: V C
authors.initials: VC
authors.lastname: Blasquez
authors.forename: M
authors.initials: M
authors.lastname: Xu
authors.forename: S C
authors.initials: SC
authors.lastname: Moses
authors.forename: W T
authors.initials: WT
authors.lastname: Garrard
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D015139:Blotting, Southern; D002460:Cell Line; D004273:DNA, Neoplasm / Q000235:genetics; D004742:Enhancer Elements, Genetic; D015870:Gene Expression; D005803:Genes, Immunoglobulin; D007145:Immunoglobulin kappa-Chains / Q000235:genetics*; D007438:Introns; D051379:Mice; D010954:Plasmacytoma / Q000235:genetics / Q000276:immunology; D010957:Plasmids; D015183:Restriction Mapping; D014162:Transfection
chemical_list: D004273:DNA, Neoplasm; D007145:Immunoglobulin kappa-Chains