Molecular cloning of a bovine immunoglobulin lambda chain cDNA

Area of Science:

• Immunogenetics
• Molecular Biology
• Bovine Genetics

Background:

• Immunoglobulin lambda light chains are crucial components of the adaptive immune system.
• Understanding the genetic basis of immunoglobulin diversity is essential for immunology and breeding programs.

Purpose of the Study:

• To identify and characterize bovine immunoglobulin (Ig) lambda light-chain cDNA clones.
• To compare the nucleotide and amino acid sequences of bovine Ig lambda chains with their human counterparts.

Main Methods:

• Construction of a bovine mammary gland cDNA library in pBR322.
• Screening using mRNA hybrid-selected translation and differential hybridization.
• Nucleotide sequencing and sequence homology analysis.

Main Results:

• Several immunoglobulin lambda light-chain clones were identified and sequenced.
• High homology observed between bovine and human Ig lambda constant and J regions.
• Bovine Ig lambda constant region shows 107 amino acids with 24 differences from human.
• Three complementarity-determining regions (CDRs) and framework regions (FRs) were identified in the variable region.
• Presence of five stop codons in the 5' end of clone 1-14E suggests transcription from a V lambda pseudogene.

Conclusions:

• Bovine and human Ig lambda chains share significant sequence homology, particularly in constant and J regions.
• The identified bovine Ig lambda cDNA sequences provide insights into the structure and evolution of these genes.
• Evidence suggests that clone 1-14E represents a pseudogene transcript, indicating potential gene inactivation or regulatory mechanisms in bovine Ig lambda loci.