Primary structure of the gene for the murine Ia antigen-associated invariant chains (Ii). An alternatively spliced exon encodes a cysteine-rich domain highly homologous to a repetitive sequence of thyroglobulin

EMBO J. 1987 Jun;6(6):1677-83. doi: 10.1002/j.1460-2075.1987.tb02417.x.


The gene for murine Ia-associated invariant (Ii) chains (Ii31 and Ii41) was characterized by sequence analysis. The gene extends over approximately 9 kb and is organized in nine exons. Exon 1 encodes the 5' untranslated region and the cytoplasmic segment, exon 2 the membrane spanning segment and adjacent amino acids and exons 3-8 the extracytoplasmic portion of Ii31. Putative promoter sequences were found upstream of the start of the coding sequence. Between exons 6 and 7 an additional, alternatively spliced exon 6b has been identified. This exon is spliced into the mRNA coding for the Ii-related Ii41 protein. Exon 6b encodes a cysteine-rich domain of 64 amino acids. It shows a remarkably high homology to the repetitive elements in thyroglobulin, a precursor for thyroid hormone. Based on this homology, it is suggested that this domain (TgR) in Tg and in Ii41 may play a role either in hormone formation or as a carrier in the transport of molecules (thyroid hormone or processed antigen respectively) between intracellular compartments.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Cysteine
  • DNA Restriction Enzymes
  • Exons
  • Genes*
  • Genes, MHC Class II*
  • Histocompatibility Antigens Class II / analysis*
  • Mice
  • RNA Splicing
  • Sequence Homology, Nucleic Acid
  • Thyroglobulin / genetics*


  • Histocompatibility Antigens Class II
  • Thyroglobulin
  • DNA Restriction Enzymes
  • Cysteine

Associated data

  • GENBANK/X05428
  • GENBANK/X05429
  • GENBANK/X05430