THE GENE ENCODING RAT-LIVER GLYCOGEN-PHOSPHORYLASE CONTAINS MULTIPLE POLYADENYLATION SIGNAL SEQUENCES

RNA blot analysis of rat liver and adipose tissues detected two glycogen phosphorylase (GP)-encoding transcripts. The polymerase chain reaction was used to characterize the 3'-noncoding region of the gene (L-GP) encoding liver-GP (L-GP) from the lean Zucker rat (Fa/Fa). Three distinct classes of colinear cDNA clones were identified by nucleotide (nt) sequence analysis, demonstrating that the L-GP gene contains at least three functional polyadenylation sites. The predominant L-GP transcript was generated by polyadenylation 130 nt 3' from the end of the coding region. A previously uncharacterized L-GP transcript is generated by polyadenylation at 346 nt 3' of the first polyadenylation site. Polyadenylation site selection does not appear to be regulated in a tissue-specific fashion. The relative steady-state L-GP mRNA levels in the different types of adipose tissues were comparable to, or exceeded transcript levels in liver.