Abstract
BackgroundThe assortment of cattle immunoglobulin and surrogate light chain genes has been extracted from the version 3.1 of Bos taurus genome sequence as a part of an international effort to sequence and annotate the bovine genome.Results63 variable lambda chain and 22 variable kappa chain genes were identified and phylogenetically assigned to 8 and 4 subgroups, respectively. The specified phylogenetic relationships are compatible with the established ruminant light chain variable gene families or subgroups. Because of gaps and uncertainties in the assembled genome sequence, the number of genes might change in the future versions of the genome sequence. In addition, three bovine surrogate light chain genes were identified. The corresponding cDNAs were cloned and the expression of the surrogate light chain genes was demonstrated from fetal material.ConclusionThe bovine kappa gene locus is compact and simple which may reflect the preferential use of the lambda chain in cattle. The relative orientation of variable and joining genes in both loci are consistent with a deletion mechanism in VJ joining. The orientation of some variable genes cannot be determined from the data available. The number of functional variable genes is moderate when compared to man or mouse. Thus, post-recombinatorial mechanisms might contribute to the generation of the bovine pre-immune antibody repertoire. The heavy chains probably contribute more to recombinational immunoglobulin repertoire diversity than the light chains but the heavy chain locus could not be annotated from the version 3.1 of Bos taurus genome.
Highlights
The assortment of cattle immunoglobulin and surrogate light chain genes has been extracted from the version 3.1 of Bos taurus genome sequence as a part of an international effort to sequence and annotate the bovine genome
The bovine immunoglobulin lambda (λ) chain locus is located on chromosome 17
Based on the phylogenetic analyses and nucleotide sequence identities in a gene region corresponding to FR1–FR3, the λ variable genes can be grouped into 8 phylogenic subgroups
Summary
The assortment of cattle immunoglobulin and surrogate light chain genes has been extracted from the version 3.1 of Bos taurus genome sequence as a part of an international effort to sequence and annotate the bovine genome. Somatic recombination during B lymphoid differentiation is required for immunoglobulin expression [1]. The genes encoding for the variable (V), diversity (D) and joining (J) segments are dispersed across a wide genomic stretch. A process called V(D)J joining brings together the specific genes for each segment type and thereby creates the second exon of a transcriptionally competent immunoglobulin gene. The recombination machinery consists of two recombination activating gene products RAG1 and RAG2 as well as various other proteins, reviewed in [2]. The cis-acting recognition signal sequences (RSSs) target the recombination machinery to the correct genomic site. Each RSS consists of heptamer (page number not for citation purposes)
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
