Multiple tRNA attachment sites in prothymosin α

Abstract

A covalent complex formed by bacterial tRNAs and prothymosin α, an abundant acidic nuclear protein involved in proliferation of mammalian cells, upon production of the recombinant rat protein in Escherichia coli cells was studied. Several tRNA attachment sites were identified in the prothymosin α molecule using a combination of deletion analysis of prothymosin α and site-specific fragmentation of the protein moiety of the prothymosin α-tRNA complex. The electrophoretic mobilities of the tRNA-linked prothymosin α and its derivatives are consistent with one tRNA molecule attached to one prothymosin α molecule, thus suggesting that alternative tRNA linking to one of several available attachment sites occurs. The possible effect of tRNA attachment on the nuclear uptake of prothymosin α is discussed.