Use of alternative polyadenylation sites by the chicken S6 ribosomal protein gene.

Two chicken ribosomal protein S6 cDNAs were isolated from a liver cDNA library and their DNA sequence determined. Each of the cDNAs was found to use a different polyadenylation signal and to be polyadenylated at a different site. This is the first observation of alternative Poly(A) site usage by a ribosmal protein gene. Northern blot analysis revealed that the chicken rpS6 transcripts can be alternatively polyadenylated in brain tissue. Southern blot analysis indicates that there is only one rpS6 gene in the chicken genome. The long open reading frame of the chicken rpS6 gene specifies 249 amino acids which show high homology with rpS6 homologues from other species. The four serine residues in rpS6 which are major sites of phosphorylation in mammals are conserved in chicken.