Cell-free translation of a T/t complex cell surface-associated gene product

The p63/6.9 protein has previously been shown to be specified by a gene within the mouse T/t complex. All wild-type chromosomes 17 specify a basic form of p63/6.9 (p63/6.9b). It is distinguishable by two-dimensional gel electrophoresis from the acidic form of p63/6.9 (p63/6.9a), which is specified by all complete t haplotypes analyzed to date. To determine whether p63/6.9 is a direct gene product of the T/t complex, testicular cytoplasmic RNA from mice bearing the genotypes +/+, +/t and t/t was translated in a rabbit reticulocyte-derived cell-free system, and translated products were analyzed by two-dimensional gel electrophoresis. The data indicate that the difference between th allelic forms of p63/6.9 is encoded within mRNA transcribed from the T/t complex. Thus p63/6.9 is the first primary gene product identified in the T/t complex. Results obtained from both cell-free translation and pulse-chase labeling experiments indicate that the mature cell surface-associated form of p63/6.9 has not undergone detectable post-translational modification.