The process, which occurs as a dividing cell ages, leading to expression of genes that are typically not expressed due to silencing by regulatory proteins.

The repair of a double-strand break in DNA in which the two broken ends are rejoined with little or no sequence complementarity. Information at the DNA ends may be lost due to the modification of broken DNA ends. This term covers instances of separate pathways, called classical (or canonical) and alternative nonhomologous end joining (C-NHEJ and A-NHEJ). These in turn may further branch into sub-pathways, but evidence is still unclear.

Repression of transcription of telomeric DNA by altering the structure of chromatin.

Repression of transcription at silent mating-type loci by alteration of the structure of chromatin.

Repression of transcription at silent mating-type loci by alteration of the structure of chromatin.

The assembly of chromatin into heterochromatin, a compact and highly condensed form that is often, but not always, transcriptionally silent.

The process in which a telomere is maintained in a specific location at the nuclear periphery.

The chemical reactions and pathways resulting in the breakdown of the transcript body of a nuclear-transcribed mRNA that is lacking a stop codon.

The directed movement of a protein-containing macromolecular complex to a specific location in the telomeric region of a chromosome.

The terminal region of a linear chromosome that includes the telomeric DNA repeats and associated proteins.

The terminal region of a linear nuclear chromosome that includes the telomeric DNA repeats and associated proteins.

The terminal region of a linear nuclear chromosome that includes the telomeric DNA repeats and associated proteins.

Any protein complex that mediates changes in chromatin structure that result in transcriptional silencing.

A condensed form of chromatin, occurring in the nucleus during interphase, that stains strongly with basophilic dyes. The DNA of heterochromatin is typically replicated at a later stage in the cell-division cycle than euchromatin.

Heterochromatic regions of the chromosome found at the telomeres of a chromosome in the nucleus.

A small, dense body one or more of which are present in the nucleus of eukaryotic cells. It is rich in RNA and protein, is not bounded by a limiting membrane, and is not seen during mitosis. Its prime function is the transcription of the nucleolar DNA into 45S ribosomal-precursor RNA, the processing of this RNA into 5.8S, 18S, and 28S components of ribosomal RNA, and the association of these components with 5S RNA and proteins synthesized outside the nucleolus. This association results in the formation of ribonucleoprotein precursors; these pass into the cytoplasm and mature into the 40S and 60S subunits of the ribosome.

A semiautonomous, self replicating organelle that occurs in varying numbers, shapes, and sizes in the cytoplasm of virtually all eukaryotic cells. It is notably the site of tissue respiration.