Kpn I Family of Long-Dispersed Repeated DNA Sequences of Man: Evidence for Entry into Genomic DNA of DNA Copies of Poly(A)-Terminated Kpn I RNAs

We have isolated eight cDNA clones complementary to the human Kpn I repeat and determined the base sequence of three. We have also determined a portion of the base sequences of three human Kpn I family members. The three cDNA sequences are extensively homologous with the 3′ends of the three genomic Kpn I family members and with a simian Kpn I family member recently described [Thayer, R. E. & Singer, M. F. (1983) Mol. Cell. Biol. 6, 967-973]. The genomic repeats terminate in regions of sequence rich in dAMP residues close to sequences at the 3′ends of the cDNA clones; a precise 3′-terminal nucleotide cannot be distinguished. These structural features are consistent with the dispersal of at least some Kpn I family members by entry into genomic DNA of copies of Kpn I RNA transcripts. Each cDNA contains a long poly(dAMP) homopolymer at its 3′end and either one or two A-A-T-A-A-A polyadenylylation signal sequences upstream from it, suggesting that Kpn I family members may be transcribed by RNA polymerase II.