Synthesis and processing of the alpha heavy chains of secreted and membrane-bound IgA.

AUTOR(ES)

Kikutani, H

RESUMO

We have compared the synthesis and processing of immunoglobulin alpha chains in two murine cell lines, a B cell lymphoma that expresses membrane-bound IgA and a hybridoma that secretes IgA. Results of biosynthetic labeling experiments demonstrated that membrane-bound and secreted alpha chains have two distinct intracellular precursors, of different molecular weights and isoelectric points. RNAs from both of these cell lines direct the synthesis in vitro of two alpha polypeptides of Mr 59,000 and 62,000, the larger one being the precursor for membrane-bound alpha chain and the smaller one being the precursor for secreted alpha chain. These cell lines each contain three RNAs, 1.7, 2.1, and 3.1 kilobases in length, which hybridize with cDNA for the alpha constant region and which are present in different concentrations. Our results suggest that the smallest RNA encodes the secreted alpha chain and one or both of the larger RNAs encode(s) the membrane-bound alpha chain.

Documentos Relacionados

• Evidence for hydrophobic region within heavy chains of mouse B lymphocyte membrane-bound IgM
• Hormone processing and membrane-bound proteinases in yeast.
• Role of an RNA cleavage/poly(A) addition site in the production of membrane-bound and secreted IgM mRNA.
• Activation of V kappa gene rearrangement in pre-B cells follows the expression of membrane-bound immunoglobulin heavy chains.
• The poliovirus receptor protein is produced both as membrane-bound and secreted forms.