Strong homology in promoter and 3'-untranslated regions of chick and rat alpha-actin genes.

We report here a comparison of the nucleotide sequences of the chick and rat skeletal muscle alpha-actin genes which reveals strongly conserved blocks of sequence in the putative transcriptional promoter and 3'-untranslated regions. This is the first instance of strong sequence conservation in untranslated gene regions between birds and mammals, other than the CAAT and ATA promoter homologies and the putative poly(A) addition signal, AATAAA. The strong conservation of these sequences suggests that they may have a role in the tissue-specific expression of the skeletal muscle alpha-actin gene.