Open AccessThe Sequence of a Large L1Md Element Reveals a Tandemly Repeated 5′ End and Several Features Found in Retrotransposons
Author(s) -
Daniel D. Loeb,
Richard W. Padgett,
Stephen C. Hardies,
W R Shehee,
Mary B. Comer,
Marshall H. Edgell,
Clyde A. Hutchison
Publication year - 1986
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.6.1.168-182.1986
Subject(s) - biology , genetics , retrotransposon , open reading frame , coding region , direct repeat , consensus sequence , sequence (biology) , homology (biology) , repeated sequence , nucleic acid sequence , base pair , genome , peptide sequence , transposable element , dna , gene
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.