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The complete sequence of the mRNA for the HLA‐DR‐associated invariant chain reveals a polypeptide with an unusual transmembrane polarity.
Author(s) -
Strubin M.,
Mach B.,
Long E.O.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb01898.x
Subject(s) - biology , complementary dna , transmembrane protein , cdna library , microbiology and biotechnology , polypeptide chain , nucleic acid sequence , peptide sequence , genetics , gene , amino acid , receptor
A non‐polymorphic polypeptide is associated intracellularly with the alpha and beta chains of murine Ia antigens and of human HLA‐DR antigens. The exact role and the structure of this invariant chain have not been determined so far. A cDNA clone encoding the 33 000 dalton human invariant chain has been isolated. The nucleotide sequence of a near full‐length cDNA clone, together with the sequence of the 5′ portion of the mRNA determined by primer‐extension, are reported here. The protein structure deduced from that sequence shows an unusual feature: the presence of a hydrophobic transmembrane region near the NH2 terminus, and of two glycosylation sites near the middle, indicates that the invariant chain has a polarity of membrane insertion which is inverted relative to histocompatibility antigens and most transmembrane proteins.