Long interspersed elements

The major forms of transposable elements in eukaryotes that lack terminal repeats belong to the class of retrotransposons. The LINEs and SINEs in mammals (long interspersed elements and short interspersed... 

Long interspersed elements (LlNEs) and short Interspersed elements (SINEs) are the most abundant mobile elements in the human genome. LlNEs account for 21 percent of human DNA SINEs, for 13 percent. 

LINE (Long INterspersed Elements) make up about 5% of the human genome. In some patients with hemophilia (a disease in which blood does not clot normally), a LINE sequence has been inserted into exon 14 of the gene for Factor VIII, a protein of the blood-clotting system. The insertion of the LINE sequence leads to the production of a nonfunctional protein. 

Additional analysis of DNA sequences in the human genome has revealed that large blocks of human genes are filled with repeated elements, including long interspersed repetitive elements (LINEs) and short interspersed repetitive elements (SINEs). Short interspersed repetitive elements such as Alu sequences are often used as target sequences for DNA fingerprinting. 

All of the mammalian transposable elements that have been characterized to date seem to be the result of transpositions that proceeded through an RNA intermediate. This process is known as retrotransposition or retroposition. Three classes of these retrotransposable elements are known in mammals (1) SINEs, or short interspersed repeated sequences such as the human Alu family and rodent Bl (2) LINEs, or long interspersed repeated sequences such as LI in a variety of mammalian species and (3) retrovirus-like elements, such as THE 1 in humans and mys and IAP in rodents. Retrovirus-like elements have long terminal repeats (LTRs) that often surround two open reading frames (ORFs) like those of retroviruses, but they lack the ability to leave one cell and enter another. LINEs also have two ORFs, but have no LTRs. SINEs have no LTRs and no ORFs. Transposition of all of these elements must involve reverse transcription of the RNA intermediate in some cases the required reverse transcriptase is apparently encoded by the element itself. 

Domain involved in protein-protein interaction, originally described in transcription factors LINl, ISLl, and MED3 Long interspersed nuclear element Liquid-liquid extraction Lower limit of detection Lower limit of quantification Large nuclear ribonucleoprotein Limit of detection logjo of odds... 

DNA propellers. The a-mitochondriate Giardia is one of the most ancestral eukaryote. It has two telomeric G4 sequences a propeller-type parallel-stranded one with three G-tetrads, and a basket type anti-parallel-stranded one with two G-tetrads. Components of the G-quadruplexes can be readily exchanged by a cut and paste principle the chromosomal ends are kept capped [388]. The giardia genome is packed with retrotransposons (both LTR-, and non-LTR-types). The non-LTR-types are LINEs (long interspersed nuclear elements) with a single ORF... 

APOBEC family apolipoproteinB mRNA-editing enzyme catalytic. Inhibits LINE (long interspersed nucleotide elements) retrotransposition in vertebrates. (Click for RNA-editing enzymes in LindiC N et al Chair Biochemistry Faculty Chemistry Chemical Technology University Ljubljana, Ljubljana, Slovenia). 

Epigenetic study subset of the NAS cohort, Boston, MA N=517 DNA methylation markers Alu, long-interspersed nuclear element (LINE-1) PbB = 4.1 xg/dl patellar Pb = 27.4 ppm tibial Pb = 20.5 Patellar Pb inversely associated with LINE-1 no association with either methylation marker for tibia Pb, PbB Wright et al. (2010)... 

Studies of overall genome composition based on reassociation kinetics (Simpson et ai, 1982 Cox et ai, 1990 Marx et a/., 2000) and analysis of fully sequenced bacterial artificial chromosome (BAC) clones from the 5. mansoni genome project show that platyhelminth genomes contain abundant highly and moderately repetitive sequence (Fig. 2.1). Much of the repetitive DNA comprises two classes of integrated mobile elements class I elements, which include long terminal repeat (LTR) retrotransposons and retroviruses, non-LTR retro-transposons and short interspersed nuclear elements (SINES) and transpose via an RNA intermediate, and class II elements (trans-posons), which transpose as DNA (Brindley et ai, 2003). Additionally, small dispersed or tandemly repeated sequences are common. A wide variety of these sequences have been isolated and characterized from a variety of taxa (Table 2.4). 

This method is useful for the isolation of interspersed repetitive DNA elements whose copy number is on the order of tens of thousands, but it will not be practical for the isolation of less abundant elements. As long as the copy number is high enough, SINEs, LINEs, and the retroviral-like elements can all be isolated using this approach. 

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