Complete sequence of a chicken lambda light chain immunoglobulin derived from the nucleotide sequence of its mRNA.

Abstract

Recombinant cDNA plasmids have been constructed from chicken spleen poly(A)-containing RNA. Two clones have been selected and provide the sequence determination of a chicken A immunoglobulin light chain: they include the complete variable, constant, and 3' untranslated regions of the chicken A light chain mRNA and part of the leader sequence. Comparison of the chicken light chain constant region with both human and mouse A constant sequences indicates 61% homology at the amino acid level. Unexpectedly, the chicken variable sequence is 53-63% homologous to human variable sequences when it is compared to the various A subgroups and only 42% homologous to the mouse VA1 sequence. The degree of homology between the variable regions of these three species does not so easily correlate with their phylogenetic relationship. Fowls offer a privileged model for studying B cell ontogeny, for they possess a primary organ of B cell differentiation, the bursa of Fabricius, which has no mammalian equivalent. In the chicken embryo, a wave of colonization of the bursa by stem cells of intraembryonic origin arises on the 8th day of development (6). From the 11th to the 14th day, la differentiation antigen and then surface immunoglobulin are progressively expressed by the progeny of these cells, until day 20, when 90% of bursal cells are surface-IgM-positive (7). Chicken B lymphocyte precursors can thus be isolated from this organ independently of the acquisition of any distinctive pre-B cell marker. They constitute a unique dynamic model for studying cellular interactions and enzymatic factors involved in the reorganization of immunoglobulin genes during the initial commitment of stem cells to the B lineage.

Rearrangement of chicken immunoglobulin genes is not an ongoing process in the embryonic bursa of Fabricius.

“…Probes used for the blot hybridization were (i) a subfragment J of the genomic X-Ch 5 phage (16) (where C = constant) of a VH cDNA plasmid. This plasmid was isolated from a selected cDNA library constructed from chicken spleen mRNA as described (17). For the synthesis of the first cDNA strand we used as primer the C,2 domain prepared from a C,] cDNA plasmid (18 Fig.…”

Amino acid sequence of heavy chain from Xenopus laevis IgM deduced from cDNA sequence: implications for evolution of immunoglobulin domains.

“…Information about the sequence of constant regions of Ig in nonmammalian vertebrates is limited to that of a chicken (6) and a frog (Rana catesbeiana) (7) light chain and most of a chicken , chain (8). We report here the sequence of a cDNA clone encoding the variable and constant regions of a ,u chain from another amphibian, Xenopus laevis, as well as the sequence corresponding to the variable region of a second clone.…”

Molecular Stability of Chicken and Rabbit Immunoglobulin G

“…After incubating the solution at 37°C for 3 hr, CD measurements were done. The results are expressed as mean residue ellipticity (8), which is defined as 8] = (100 x 8 0bs )/(l x c), where 8 0bs is the observed ellipticity in· degrees, c is the concentration in residue moles/ liter, and I is the lightpath length (cm). A value of 108 was used as the mean residue molecular weight.…”