The complete sequence of the mRNA for the HLA‐DR‐associated invariant chain reveals a polypeptide with an unusual transmembrane polarity.
The complete sequence of the mRNA for the HLA‐DR‐associated invariant chain reveals a polypeptide with an unusual transmembrane polarity.
复制标题
HLA-DR-相关不变链的 mRNA 完整序列揭示了一种具有不寻常跨膜极性的多肽。
作者：
M. Strubin;B. Mach;Eric O Long
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.
