Linked Life Data

7968491

Source:http://linkedlifedata.com/resource/pubmed/id/7968491

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1994-12-2
pubmed:abstractText
All mammalian genomes contain approximately 100,000 copies of the transposable element LINES-1 (L1). Phylogenetic analysis indicates that the L1 progenitor predates the mammalian radiation; since that time, the open reading frames encoded in L1 have evolved under selection. The least conserved regions within L1 are the 5'-terminal transcriptional regulatory sequences. In rodents, four types of L1 elements (A, F, and V from mouse and R from rat) have been defined according to the type of apparently nonhomologous promoter sequence present at the 5' end. In this study, we investigate the relationships between these four types of promoters. DNA sequence was determined from approximately 1.5-kb regions from the 5' ends of seven F- and three V-type L1 elements. These sequences were aligned with 29 previously reported L1 elements. Phylogenetic analysis was then performed on the homologous regions of the alignment. The results indicate that in mouse all of the A-, F-, and V-type elements belong to a single dominant lineage but were inserted into the genome during different time periods; V-type elements are the oldest, while A-type elements are the most recently inserted. V-type elements also appear ancestral to the R-type elements found in rat and therefore were replicatively competent prior to the divergence of rat and mouse. Analysis of sequence identity indicates that the different 5' promoters did not derive from a common ancestor. Therefore, the dominant L1 lineage appears to have acquired novel promoter sequences from non-L1 sources. Transposable elements from a wide range of species show similar structural rearrangements, suggesting that acquisition of new sequences may be a common theme in their evolution.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0737-4038
pubmed:author
pubmed:issnType
Print
pubmed:volume
11
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
778-89
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed:year
1994
pubmed:articleTitle
Rodent L1 evolution has been driven by a single dominant lineage that has repeatedly acquired new transcriptional regulatory sequences.
pubmed:affiliation
Department of Microbiology and Immunology, University of North Carolina at Chapel Hill 27599-7290.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, U.S. Gov't, P.H.S.