title: [Conformational polymorphysm of G-rich fragments of DNA ALU-repeats. I. Potential noncanonical structures].
abstract: In this paper, we report results of systematic studies of conformational polymorphism of G-rich DNA fragments from Alu repeats. Alu retrotransposones are primate-specific short interspersed elements. Using the Alu sequence from the prooncogen bcl2 intron and the consensus AluSx sequence as representative examples, we determined characteristic Alu sites that are capable of adopting G-quadruplex (GQ) conformations (i.e., potential quadruplex sites - PQSAlu), and demonstrated by bioinformatics methods that those sites are Alu-specific in the human genome. Genomic frequencies of PQSAlu were assessed (~1/10000 b.p.). The sites were found to be characteristic of young (active) Alu families (Alu-Y). A recombinant DNA sequence bearing the Alu element from the human bcl2 gene (304 b.p.) and its PQS-mutant (Alu-PQS) were constructed. The formation of noncanonical structures in Alubcl2 dsDNA and the absence of such structures in the case of Alu-PQS were shown using DMS-footprinting and AFM microscopy. Expression vectors bearing wild-type and mutant Alu insertions in the promoter regions were obtained, and the effects of these insertions on the expression of the reporter gene in НЕК293 and HeLa cell lines were compared. Our findings on the spatial organization of Alu repeats may provide insight into the mechanisms of genomic rearrangements which underlie many oncological and neurodegenerative diseases.
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: A V
authors: AV
authors: Sekridova
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: A M
authors: AM
authors: Varizhuk
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: O N
authors: ON
authors: Tatarinova
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: V V
authors: VV
authors: Severov
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: N A
authors: NA
authors: Barinov
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: I P
authors: IP
authors: Smirnov
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: V N
authors: VN
authors: Lazarev
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: D V
authors: DV
authors: Klinov
authors: Federal Research and Clinical Center of Physical-Chemical Medicine, Moscow, Russia.
authors: G E
authors: GE
authors: Pozmogova
mesh_terms: D020087:Alu Elements; D000818:Animals; D019556:COS Cells; D002522:Chlorocebus aethiops; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D007438:Introns; D009154:Mutation; D009690:Nucleic Acid Conformation; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics* / Q000378:metabolism
chemical_list: C000595707:BCL2 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2
keywords: Alu-repeats; G-quadruplex DNA; dynamics of DNA secondary structures