We have isolated both the genomic and cDNA clones of the actin gene of Pneumocystis carinii and analyzed its genomic structure. The gene consists of eight exons. The introns are uniformly short in size (43-49 nucleotides). Multiple poly(A) sites of the actin mRNA are located in a highly AT-rich portion of the 3′-flanking region of this gene, although the canonical poly(A) signal, AATAAA, is not found in the region. Transcription initiation sites have been determined by the primer extension method. A TATA-box-like sequence is located 39-bp upstream of the 5′-most major initiation site.
ASJC Scopus subject areas