Heavy chain V region diversity in the duck-billed platypus (Ornithorhynchus anatinus): long and highly variable complementarity-determining region 3 compensates for limited germline diversity

J Immunol. 2002 May 15;168(10):5155-62. doi: 10.4049/jimmunol.168.10.5155.

Abstract

In this work, to study the emergence of the H chain V region repertoire during mammalian evolution, we present an analysis of 25 independent H chain V regions from a monotreme, the Australian duck-billed platypus, Ornithorhynchus anatinus. All the sequences analyzed were found to form a single branch within the clan III of mammalian V region sequences in a distance tree. However, compared with a classical V gene family this branch was more diversified in sequence. Sequence analysis indicates that the apparent lack of diversity in germline V segments is well compensated for by relatively long and highly diversified D and N nucleotides. In addition, extensive sequence variation was observed in the framework region 3. Furthermore, at least five and possibly seven different J segments seem to be actively used in recombination. Interestingly, internal cysteine bridges in the complementarity-determining region (CDR)3 loop, or between the CDR2 and CDR3 loops, are found in approximately 36% of the platypus V(H) sequences. Such cysteine bridges have also been observed in cow, camel, and shark. Internal cysteine bridges may play a role in stabilizing long and diversified CDR3 and thereby have a role in increasing the affinity of the Ab-Ag interaction.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Antibody Diversity* / genetics
  • Base Sequence
  • Cattle
  • Cloning, Molecular
  • Complementarity Determining Regions / analysis
  • Complementarity Determining Regions / genetics
  • DNA, Complementary / analysis
  • Germ-Line Mutation / immunology*
  • Immunoglobulin Heavy Chains / analysis*
  • Immunoglobulin Heavy Chains / genetics
  • Immunoglobulin Variable Region / analysis*
  • Immunoglobulin Variable Region / genetics
  • Molecular Sequence Data
  • Multigene Family / immunology
  • Platypus / genetics
  • Platypus / immunology*
  • Sequence Alignment / methods

Substances

  • Complementarity Determining Regions
  • DNA, Complementary
  • Immunoglobulin Heavy Chains
  • Immunoglobulin Variable Region

Associated data

  • GENBANK/AF381289
  • GENBANK/AF381290
  • GENBANK/AF381291
  • GENBANK/AF381292
  • GENBANK/AF381293
  • GENBANK/AF381294
  • GENBANK/AF381295
  • GENBANK/AF381296
  • GENBANK/AF381297
  • GENBANK/AF381298
  • GENBANK/AF381299
  • GENBANK/AF381300
  • GENBANK/AF381301
  • GENBANK/AF381302
  • GENBANK/AF381303
  • GENBANK/AF381304
  • GENBANK/AF381305
  • GENBANK/AF381306
  • GENBANK/AF381307
  • GENBANK/AF381308
  • GENBANK/AF381309
  • GENBANK/AF381310
  • GENBANK/AF381311
  • GENBANK/AF381312
  • GENBANK/AF381313
  • GENBANK/AF381314
  • GENBANK/AF381315
  • GENBANK/AF381316
  • GENBANK/AF381317
  • GENBANK/AF381318
  • GENBANK/AF381319
  • GENBANK/AF381320
  • GENBANK/AF381321
  • GENBANK/AF381322
  • GENBANK/AF381323
  • GENBANK/AF381324