Rearrangement and expression of kappa light chain genes can occur without mu heavy chain expression during differentiation of pre-B cells.
The kinetics of kappa light (kappa L) chain gene rearrangement and expression on mRNA and protein level has been studied with four stromal cell/IL-7 reactive, long-term in vitro proliferating pre-B cell lines and clones, two from fetal liver of normal mice and two from fetal liver of E microH-bcl-2 transgenic (bcl-2-tg) mice. These pre-B cell lines and clones are DJH-rearranged on both H chain alleles. Two of the clones harbor H chain rearrangements which do not allow the expression of VHDJH rearranged H chain genes as microH chain proteins. Upon removal of IL-7 from the pre-B cell cultures all four cell lines rearrange VH-DJH and VL-JL gene segments, loose the surface expression of c-kit, CD43, and surrogate light chain, as well as the capacity to be clonable on stromal cells in the presence of IL-7. Pre-B cells from normal mice die by apoptosis during differentiation, while those from bcl-2-tg mice do not. All four lines and clones express comparable levels of mRNA for microH and kappa L chains with the same time kinetics during 3 days of differentiation. However, only two of the four pre-B cell lines and clones express microH chain protein, whereas all four pre-B cell lines and clones express kappa L chain protein at comparable levels between 2 x 10(5) and 1.4 x 10(6) kappa L chain molecules per cell. These results suggest that microH chain expression is not mandatory for rearrangement and normal expression of kappa L chain genes when pre-B cells differentiate to B cells.
Grawunder
U
U
Basel Institute for Immunology, Switzerland.
Haasner
D
D
Melchers
F
F
Rolink
A
A
D000818:Animals; D000911:Antibodies, Monoclonal; D001402:B-Lymphocytes / Q000502:physiology*; D001483:Base Sequence; D015152:Blotting, Northern; D015153:Blotting, Western; D002454:Cell Differentiation / Q000276:immunology; D002460:Cell Line; D005314:Embryonic and Fetal Development; D005260:Female; D005434:Flow Cytometry; D005786:Gene Expression Regulation / Q000502:physiology*; D015328:Gene Rearrangement, B-Lymphocyte, Light Chain / Q000502:physiology*; D007147:Immunoglobulin Light Chains; D054444:Immunoglobulin Light Chains, Surrogate; D007145:Immunoglobulin kappa-Chains / Q000096:biosynthesis* / Q000235:genetics; D007148:Immunoglobulin mu-Chains / Q000096:biosynthesis; D008562:Membrane Glycoproteins / Q000096:biosynthesis; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008969:Molecular Sequence Data
D000911:Antibodies, Monoclonal; D007147:Immunoglobulin Light Chains; D054444:Immunoglobulin Light Chains, Surrogate; D007145:Immunoglobulin kappa-Chains; D007148:Immunoglobulin mu-Chains; D008562:Membrane Glycoproteins