[Intranuclear ion fountains as regulators of genome work: fountain hypothesis of dominance and some epigenetic effects].
It is hypothesized that gene function is modulated through the action of the ion channels of the internal nuclear membrane, and that this underlies the phenomenon of dominance and some epigenetic effects. The topographic specificity essential to gene regulation by injecting portions of ions--ion fountains--is ensured by special fountain RNAs (fRNAs), which operate as double-stranded molecules, and fions, the fRNA-binding sites on the DNA. Every specific fion.fRNA complex then binds with the protein of an ion channel in the inner nuclear membrane, whereby this channel briefly opens to dispense, e.g., Ca2+, Zn2+, or K+ from the perinuclear cistern into the nucleus, as defined by the specificity of fRNA, fion, and the channel chosen by them. Fions may be situated both in introns of genes and at their flanks, even quite far from the target gene. Allelic fions, that is, fions located in homologous sites of homologous chromosomes but differing in the capacity of binding different fRNAs, will unequally influence the ionic surroundings of their structural genes. Ion channels can provide the dominant allele with an ionic atmosphere dissimilar from that of the recessive allele. Distinctions in the nature, number, and location of fions may be the main reason why the dominant and recessive alleles of a structural gene differ in activity even though their other properties are identical. Unequal changes occurring in the vicinity of the alleles may involve chromatin configuration, transcriptional activity of the gene, mRNA processing and lifespan. Isolation of structural genes in a chromosome by long intergene spacers, and large distances between chromosomes in the nucleus prevent undesirable interference of ion fountains. Fions may be key components of many enhancers and silencers. The performance of fions may be affected by pairing of homologous nucleotide sequences of chromosomes, which generates a number of epigenetic effects, such as transvection and gene position effect. Excessive approach of a structural gene to inadequate ion fountains may cause unscheduled chromatin compaction and gene suppression.
A M
AM
Olovnikov
D002412:Cations; D005799:Genes, Dominant; D005808:Genes, Recessive; D016678:Genome; D012313:RNA / Q000235:genetics
D002412:Cations; D012313:RNA