LOCALIZATION OF SATELLITE DNA AND ASSOCIATED PROTEIN IN RESPECT TO NUCLEOLAR PRECURSOR BODIES
IN ONE- AND TWO-CELL MOUSE EMBRYOS
E. V. Gavrilova,1, * I. S. Kuznetsova,1 N. I. Enukashvily,1 E. M. Noniashvily,2
A. P. Dyban,2 O. I. Podgornaya 1
1 Institute of Cytology RAS, and 2 Institute of Experimental Medicine RAMN, St. Petersburg;
* e-mail: shelbys@mail.ru
Nucleolar precursor bodies (NPB) are characteristic structures in the nuclei of one- and two cell mouse embryos. The alignment of centromeric (CEN) and
pericentromeric (periCEN) chromosome regions to the chromatin layer surrounding NPB is known. Mus musculus 4 satellite DNA (satDNA) types are known
to be located in CEN region - mouse minor satellite (MiSat) and mouse satellite 3 (MS3); and periCEN region - mouse major satellite (MaSat) and mouse satellite
(MS4). We determined the localization of 4 types of mouse satDNA CEN and periCEN regions and associated proteins: RNA-helicase p68, SMC3, Rad21 subunits
of the cohesin complex and SYCP3 subunit of the synaptonemal complex (SC). Partially flattened nuclei of the one- and two-cell embryos and embiyos treated with
ocadaic acids (OA) were used. Different satDNA fragments revealed distinct domains at the surface of NPB: periCEN MaSat was always localized in NPB more
internally covering almost entire surface of NPB while CEN MiSat, MS3 and periCEN MS4 showed more peripheral localization. All 4 satDNA did not cover the entire
areas of the NPB, indicating the presence of other DNA sequence involved in its formation. RNA-helicase p68 and components of multiprotein cohesin and
synaptonemal complexes are the necessary components of NPB. Our results support the opinion that NPB serve as a precursor of chromocenters.
Key words: centromere region, pericentromere region, satellite DNA, nucleolar precursor bodies, RNA-helicase p68, proteins of cohesin and
synaptonemal complexes
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