The Chinese hamster Alu-equivalent sequence: a conserved highly repetitious, interspersed deoxyribonucleic acid sequence in mammals has a structure suggestive of a transposable element.

Abstract

A consensus sequence has been determined for a major interspersed deoxyribonucleic acid repeat in the genome of Chinese hamster ovary cells (CHO cells). This sequence is extensively homologous to (i) the human Alu sequence (P. L. Deininger et al., J. Mol. Biol., in press), (ii) the mouse B1 interspersed repetitious sequence (Krayev et al., Nucleic Acids Res. 8:1201-1215, 1980) (iii) an interspersed repetitious sequence from African green monkey deoxyribonucleic acid (Dhruva et al., Proc. Natl. Acad. Sci. U.S.A. 77:4514-4518, 1980) and (iv) the CHO and mouse 4.5S ribonucleic acid (this report; F. Harada and N. Kato, Nucleic Acids Res. 8:1273-1285, 1980). Because the CHO consensus sequence shows significant homology to the human Alu sequence it is termed the CHO Alu-equivalent sequence. A conserved structure surrounding CHO Alu-equivalent family members can be recognized. It is similar to that surrounding the human Alu and the mouse B1 sequences, and is represented as follows: direct repeat-CHO-Alu-A-rich sequence-direct repeat. A composite interspersed repetitious sequence has been identified. Its structure is represented as follows: direct repeat-residue 47 to 107 of CHO-Alu-non-Alu repetitious sequence-A-rich sequence-direct repeat. Because the Alu flanking sequences resemble those that flank known transposable elements, we think it likely that the Alu sequence dispersed throughout the mammalian genome by transposition.

Species-specific homogeneity of the primate Alu family of repeated DNA sequences

“…Renarkably, the rodent Alu family equivalents are organized as 130 bp nDncsEric sequences (4,5,13,14,15,16). In spite of nurerous DNA sequencing studies, there are no examples of a 300 bp dimeric organization, like that found in human, within the rodent gemones.…”

“…Closely related families of repetitive sequences, called Bi or Aluequivalent families, have been cbserved in muse (13), Chinese hamster (14,15) and rat DNAs (16). Renarkably, the rodent Alu family equivalents are organized as 130 bp nDncsEric sequences (4,5,13,14,15,16).…”

The L1Md long interspersed repeat family in the mouse: almost all examples are truncated at one end

“…Length variation exists in both of these two types of repeats. Small insertions and deletions within the "discrete" repetitive elements account for variations in the repeat length (9). The length of clustered and scrambled repetitive elements would depend upon the particular arrangement of each repeat (10).…”

Interspersed repeated sequences in the African green monkey genome that are homologous to the human Alu family

“…5) and 101 is repeated with 80 percent homology from residues 192 to 236. These 2 homologous regions overlap 40 bp stretches (starting at residues 78 and 212, respectively) that have been observed to be highly conserved in human Alus and in rodent interspersed repeated sequence (36)(37)(38). The A residues at the end of the monkey sequence are preceded by a repetitive oligonucleotide AGAGAGAG that is complementary to the sequence TCTC found at a similar position in several human Alu sequences (18,37,39,40).…”