Nucleolar dominance and ribosomal RNA gene silencing.
نویسندگان
چکیده
Nucleolar dominance is an epigenetic phenomenon that occurs in genetic hybrids and describes the expression of 45S rRNA genes inherited from one progenitor due to the silencing of the other progenitor's rRNA genes. Nucleolar dominance is a manifestation of rRNA gene dosage control, which also occurs in non-hybrids, regulating the number of active rRNA genes according to the cellular demand for ribosomes and protein synthesis. Ribosomal RNA gene silencing involves changes in DNA methylation and histone modifications, but the molecular basis for choosing which genes to silence remains unclear. Recent studies indicate a role for short interfering RNAs (siRNAs) or structured regulatory RNAs in rRNA gene silencing in plants or mammals, respectively, suggesting that RNA may impart specificity to the choice mechanism.
منابع مشابه
Ribosomal RNA gene silencing in interpopulation hybrids of Tigriopus californicus: nucleolar dominance in the absence of intergenic spacer subrepeats.
A common feature of interspecific animal and plant hybrids is the uniparental silencing of ribosomal RNA gene transcription, or nucleolar dominance. A leading explanation for the genetic basis of nucleolar dominance in animal hybrids is the enhancer-imbalance model. The model proposes that limiting transcription factors are titrated by a greater number of enhancer-bearing subrepeat elements in ...
متن کاملGene dosage and stochastic effects determine the severity and direction of uniparental ribosomal RNA gene silencing (nucleolar dominance) in Arabidopsis allopolyploids.
Nucleolar dominance is an epigenetic phenomenon in which one parental set of ribosomal RNA (rRNA) genes is silenced in an interspecific hybrid. In natural Arabidopsis suecica, an allotetraploid (amphidiploid) hybrid of Arabidopsis thaliana and Cardaminopsis arenosa, the A. thaliana rRNA genes are repressed. Interestingly, A. thaliana rRNA gene silencing is variable in synthetic Arabidopsis suec...
متن کاملPostembryonic Establishment of Megabase-Scale Gene Silencing in Nucleolar Dominance
Nucleolar dominance is an epigenetic phenomenon in plant and animal genetic hybrids that describes the expression of 45S ribosomal RNA genes (rRNA genes) inherited from only one progenitor due to the silencing of the other progenitor's rRNA genes. rRNA genes are tandemly arrayed at nucleolus organizer regions (NORs) that span millions of basepairs, thus gene silencing in nucleolar dominance occ...
متن کاملNucleolar dominance and silencing of transcription.
Nucleolar dominance is a phenomenon in plant and animal hybrids whereby one parental set of ribosomal RNA (rRNA) genes is transcribed, but the hundreds of rRNA genes inherited from the other parent are silent. The phenomenon gets it name because only transcriptionally active rRNA genes give rise to a nucleolus, the site of ribosome assembly. Nucleolar dominance provided the first clear example ...
متن کاملLocus-Specific Ribosomal RNA Gene Silencing in Nucleolar Dominance
The silencing of one parental set of rRNA genes in a genetic hybrid is an epigenetic phenomenon known as nucleolar dominance. We showed previously that silencing is restricted to the nucleolus organizer regions (NORs), the loci where rRNA genes are tandemly arrayed, and does not spread to or from neighboring protein-coding genes. One hypothesis is that nucleolar dominance is the net result of h...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Current opinion in cell biology
دوره 22 3 شماره
صفحات -
تاریخ انتشار 2010