Isolation of the specific mRNA coding for a CALLA-like protein and partial characterization of its cell-free...

In a cell-free translation directed mRNA from the human lymphoblastoid cell line KM3, common ALL-Antigen (CALLA)-like proteins were detected immunologically. For immunoprecipitation a combination of three monoclonal antibodies and a rabbit heteroantiserum with anti-CALLA specificity were used. Employing a cocktail of two anti-CALLA monoclonal antibodies CALLA directing mRNA could be purified by specific polysomal immunoadsorption. The CALLA-like protein defined in the cell-free products of total mRNA and mRNA derived from polysomes showed a Mr of 95,000 daltons. Additional CALLA-like proteins could be identified in the cell-free translational products when mRNA from polysomes precipitated by the anti-CALLA heteroantiserum was used. The calculated Mr of these proteins were 80,000 97,000 and 135,000 daltons.