The Ig light chain restricted B6. Kappa super(-) lambda super(SEG) mouse strain suggests that the IGL locus genomic organization is subject to constant evolution

• Published in: Immunogenetics (New York) Vol. 54; no. 2; pp. 106 - 119
• Main Authors: Amrani, YI, Voegtle, D, Montagutelli, X, Cazenave, P A, Six, A
• Format: Journal Article
• Language: English
• Published: 01-05-2002
• ISSN: 0093-7711
• DOI: 10.1007/s00251-002-0448-6

In laboratory mice, the different Ig lambda light chain subtypes ( lambda 1, lambda 2, lambda x and lambda 3) are expressed on 60, 16, 16 and 8%, respectively, of the lambda -positive peripheral B cells. Eighteen years ago, our laboratory characterized a lambda 1 super(-) wild mouse strain: SPE (Mus spretus). In this report, we describe the characterization of another wild-derived Mus spretus inbred strain, SEG, that presents the same characteristic, namely the absence of lambda 1 expression. An almost congenic strain, B6. lambda super(SEG), was detected in a series of recombinant congenic strains carrying 2% of SEG/Pas genome in a C57BL/6J background. This B6. lambda super(SEG) strain was crossed to Igh super(a) C Kappa super(-) mice in order to derive two different additional congenic strains: B6. Kappa super(-) lambda super(SEG) Igh super(a) and B6. Kappa super(-) lambda super(SEG) Igh super(b). In this paper, we characterize the genomic organization and the expression of the SEGIGL locus. Altogether, our data show that the SEGIGL locus is constituted by a single functional IGLJ2SEG-IGLC2SEG, two pseudo IGLJ4SEG1/2-IGLC4SEG1/2 gene clusters and two V gene segments: IGLV2SEG and IGLVXSEG. In particular, we show the absence of IGLV1 and IGLVSD26 gene segments. IGLVSD26 was reported to be present in some Mus m. musculus mice and absent in BALB/c. Here, we confirm its presence not only in other Mus m. musculus mice but also in Mus spretus mice. Consequently, we propose that IGLVSD26-related gene segments define a new family that we name V lambda 4. The study of the organization of different IGL loci, in addition to the V lambda 4 super(+) reported here, could elucidate questions concerning the evolution of the lambda locus.