Alpha-actinin synthesis can be modulated by antisense probes and is autoregulated in non-muscle cells.

We used a 279 bp cDNA probe derived from a Dictyostelium alpha-actinin genomic sequence to assay the degree of homology between alpha-actinin from slime molds, mammalian and chicken cells. Recognition of this probe by vertebrate cells was shown in Southern and Northern blots, and by antisense RNA-induced depression of endogenous alpha-actinin synthesis in living cells. Micro-injection of Dictyostelium or chicken gizzard alpha-actinin resulted in incorporation of these proteins in stress fibers, peripheral microfilament belts and adhesion sites. Alpha-actinin-injected cells showed a marked, transient reduction of synthesis of the corresponding endogenous protein. These data emphasize the high degree of conservation of alpha-actinin during evolution and show for the first time autoregulation of synthesis for a microfilament protein.