The sequence of a large L1Md element reveals a tandemly repeated 5' end and several features found in retrotransposons

Mol Cell Biol. 1986 Jan;6(1):168-82. doi: 10.1128/mcb.6.1.168-182.1986.


The complete nucleotide sequence of a 6,851-base pair (bp) member of the L1Md repetitive family from a selected random isolate of the BALB/c mouse genome is reported here. Five kilobases of the element contains two overlapping reading frames of 1,137 and 3,900 bp. The entire 3,900-bp frame and the 3' 600 bp of the 1,137-bp frame, when compared with a composite consensus primate L1 sequence, show a ratio of replacement to silent site differences characteristic of protein coding sequences. This more closely defines the protein coding capacity of this repetitive family, which was previously shown to possess a large open reading frame of undetermined extent. The relative organization of the 1,137- and 3,900-bp reading frames, which overlap by 14 bp, bears resemblance to protein-coding, mobile genetic elements. Homology can be found between the amino acid sequence of the 3,900-bp frame and selected domains of several reverse transcriptases. The 5' ends of the two L1Md elements described in this report have multiple copies, 4 2/3 copies and 1 2/3 copy, of a 208-bp direct tandem repeat. The sequence of this 208-bp element differs from the sequence of a previously defined 5' end for an L1Md element, indicating that there are at least two different 5' end motifs for L1Md.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Composition
  • Cloning, Molecular
  • DNA Restriction Enzymes
  • DNA Transposable Elements*
  • Genes*
  • Globins / genetics
  • Mice
  • Mice, Inbred BALB C
  • Phylogeny
  • Repetitive Sequences, Nucleic Acid
  • Retroviridae / genetics


  • DNA Transposable Elements
  • Globins
  • DNA Restriction Enzymes

Associated data

  • GENBANK/M13002