Mustafin R N, Khusnutdinova E K
Bashkir State University, Ufa, 450076, Russia.
Biochemistry (Mosc). 2018 Mar;83(3):185-199. doi: 10.1134/S000629791803001X.
Systems initially emerged for protecting genomes against insertions of transposable elements and represented by mechanisms of splicing regulation, RNA-interference, and epigenetic factors have played a key role in the evolution of animals. Many studies have shown inherited transpositions of mobile elements in embryogenesis and preservation of their activities in certain tissues of adult organisms. It was supposed that on the emergence of Metazoa the self-regulation mechanisms of transposons related with the gene networks controlling their activity could be involved in intercellular cell coordination in the cascade of successive divisions with differentiated gene expression for generation of tissues and organs. It was supposed that during evolution species-specific features of transposons in the genomes of eukaryotes could form the basis for creation of dynamically related complexes of systems for epigenetic regulation of gene expression. These complexes could be produced due to the influence of noncoding transposon-derived RNAs on DNA methylation, histone modifications, and processing of alternative splicing variants, whereas the mobile elements themselves could be directly involved in the regulation of gene expression in cis and in trans. Transposons are widely distributed in the genomes of eukaryotes; therefore, their activation can change the expression of specific genes. In turn, this can play an important role in cell differentiation during ontogenesis. It is supposed that transposons can form a species-specific pattern for control of gene expression, and that some variants of this pattern can be favorable for adaptation. The presented data indicate the possible influence of transposons in karyotype formation. It is supposed that transposon localization relative to one another and to protein-coding genes can influence the species-specific epigenetic regulation of ontogenesis.
最初出现的用于保护基因组免受转座元件插入影响的系统，以剪接调控、RNA干扰机制和表观遗传因子为代表，在动物进化中发挥了关键作用。许多研究表明，移动元件在胚胎发育过程中存在遗传转座现象，并在成年生物体的某些组织中保持其活性。据推测，后生动物出现时，与控制转座子活性的基因网络相关的转座子自我调控机制，可能参与了细胞连续分裂级联过程中的细胞间协调，伴随分化基因表达以生成组织和器官。据推测，在进化过程中，真核生物基因组中转座子的物种特异性特征，可能构成创建动态相关的基因表达表观遗传调控系统复合体的基础。这些复合体可能是由于非编码转座子衍生RNA对DNA甲基化、组蛋白修饰和可变剪接变体加工的影响而产生的，而移动元件本身可能直接参与顺式和反式基因表达的调控。转座子广泛分布于真核生物基因组中；因此，它们的激活可改变特定基因的表达。反过来，这在个体发育过程中的细胞分化中可能发挥重要作用。据推测，转座子可形成物种特异性的基因表达控制模式，且该模式的某些变体可能有利于适应。所呈现的数据表明转座子在核型形成中可能产生的影响。据推测，转座子彼此之间以及与蛋白质编码基因的定位，可影响物种特异性的个体发育表观遗传调控。
