POLYMORPHISM OF MICROSATELLITE REPEATS AND THEIR
RELATION WITH THE MECHANISMS OF GENE
TRANSCRIPTION REGULATION
A.V. Pheophilov, V.I. Glazko
Russian State Agrarian University – Moscow Agricultural Academy named after K.A.
Timiryazev, Moscow, Russia
E-mail: foton87@yahoo.com, vglazko@yahoo.com
Keywords: inverted repeats, ISSR, purine/pyrimidine tracks, transcription regulation
Motivation and Aim: Control and management over genetic resources of wild and
domestic animals and plants is determined by availability of testing systems which
allow reliable identification of specific traits of genetic structures of species, breed and
varieties. One direction of such systems’ creation is an estimation of polymorphism of
DNA inverted repeats' positioning (ISSR-PCR).
Methods and Algorithms: In purposes of estimation of their informational value the
comparative analysis of DNA of several cattle, sheep breeds, bisons and aurochs by
using of micro satellite loci fragments (GA)9C, (AG)9C, (AC)9T (ACC)6G, (GAG)6C,
(AGC)6C, (AGC)6G, (CTC)6C as primers in PCR was carried out. Data about species
and breed specific features of combinations of DNA fragments of various length
(amplicons) were obtained.
Results: Most of them were revealed by using as the primers in PCR of
purine/pyrimidine tracks which could take part in triplex DNA structure formation and
gene expression regulation [1]. Amplicon spectra received by using two of such tracks
(AG)9C and (GA)9C on DNA of cattle and sheep breeds showed more polymorphous
DNA fragments for (AG)9C in comparison with (GA)9C ones. Genbank search with
using BLAST algorithms allowed to localize these tracks in genes of II class MHC,
moreover (GA)9C was observed both in sheep and cattle exons, that could be lead to
relative higher conservatism of amplicon length in (GA)9C spectra. At the same time
GAGAG sequence is the consensus one for the GAF transcription regulation factor [2,
3], and (GA)n repeats are the targets of CTCF binding which plays the key role in
chromatin folding, changes of which related with the replacing of the gene expression
programs [4]. Data obtaining testified the dependence between length polymorphism of
DNA fragments flanked by inverted repeats of microsatellite loci and nucleotide
sequence of such locus and higher levels of polymorphism of those amplicon spectra
which flanks belong to purine/pyrimidine tracks, among which it's lower for GA
containing sequences. Conservatism of the latter may be caused by involving of GA
repeats into binding with the proteins, which take part in regulation of gene transcription
programs, in particular by means of influence on chromatin folding.
Conclusion: Using of such fragments for polyloci genotyping of animal genome DNA
allows reveal the combinations of DNA fragments with the different lengths which may
be considered as gene pool “barcode” for species, breeds and individual animal.
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