ISSN:
1432-1211
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Medicine
Notes:
Abstract To assess the role interleukins and mitogens play in regulating immunoglobulin (Ig) gene expression via the Ig enhancer and promoter, transgenic mice carrying two different Ig gene regulatory regions were generated. One, EμkCAT, contains the Ig heavy chain enhancer (Eμ) and the κ light chain promoter driving the chloramphenicol acetyltransferase (CAT) gene. In the other, ΔEμkCAT, CAT is under the control of the κ promoter alone. Eμ and κ relative activity were assessed by CAT assay. In EμkCAT mice, low CAT expression was consistently found in spleen, bone marrow, mesenteric lymph node, and thymus but not in brain, lung, or kidney. In ΔEμkCAT mice, CAT expression was detectable just above background in lymphoid tissues, suggesting a basic level of tissue specificity in the absence of the enhancer. Whole spleen cell cultures prepared from the mice were treated with lymphokines and mitogens. Lipopolysaccharide (LPS), concanavilin A (Con A), interleukin 6 (IL-6), and interferon-γ (IFN-γ) increased CAT expression to varying extents in cells derived from EμkCAT mice but not in spleen cells prepared from EμkCAT mice. Thus, the presence of Eμ, in addition to the ϰ promoter, is essential for the stimulation of CAT expression mediated by these factors. B cells from EμkCAT mice were separated by density into populations of small and large cells. In untreated small B cells, no CAT expression was detected and only addition of LPS resulted in an increase in CAT expression. In large B cells, CAT was expressed at a low level without addition of exogenous factors. Incubation with LPS, IL-6, Con A and IFN-γ caused CAT expression to increase several-fold. This transgenic system provides a means to identify exogenous factors that activate Ig enhancers and promoters.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00216623
Permalink