telomeric D-loop binding

Definition

Target type: molecularfunction

Binding to a telomeric D-loop. A telomeric D-loop is a three-stranded DNA displacement loop that forms at the site where the telomeric 3' single-stranded DNA overhang (formed of the repeat sequence TTAGGG in mammals) is tucked back inside the double-stranded component of telomeric DNA molecule, thus forming a t-loop or telomeric-loop and protecting the chromosome terminus. [GOC:BHF, GOC:BHF_telomere, GOC:nc, PMID:19734539]

Telomeric D-loop binding is a crucial process in maintaining the integrity and stability of chromosome ends. It involves the interaction of specific proteins with the D-loop structure, which is a three-stranded DNA structure formed during telomere replication. The D-loop is formed when the 3' overhang of the G-rich strand of the telomere invades the duplex DNA, displacing one of the strands to form a loop.

The molecular function of telomeric D-loop binding can be described in terms of the following key aspects:

1. **Protection of Telomeres:** D-loop binding proteins, such as POT1 and TRF2, shield the telomeric DNA from degradation by exonucleases and prevent the activation of DNA damage response pathways. This is essential for maintaining the integrity of chromosome ends and preventing premature senescence or cell death.

2. **Regulation of Telomere Length:** Telomeric D-loop binding proteins play a role in regulating telomere length by influencing the activity of telomerase, the enzyme that adds repetitive DNA sequences to telomeres. D-loop binding can modulate the access of telomerase to the telomeric DNA, controlling the rate of telomere elongation.

3. **Chromatin Remodeling:** D-loop binding can influence the organization of chromatin at telomeres, affecting the accessibility of telomeres to other proteins and processes. This can impact gene expression and other cellular functions.

4. **DNA Replication:** D-loop binding is involved in the replication of telomeres, ensuring that the ends of chromosomes are duplicated accurately during cell division. This is crucial for maintaining genomic stability and preventing the loss of genetic information.

5. **Prevention of End-to-End Fusion:** D-loop binding proteins help prevent the fusion of chromosome ends, which can lead to chromosomal instability and cell death. They do this by ensuring that the telomeres are properly capped and protected from illegitimate recombination events.

Overall, telomeric D-loop binding is a complex molecular process that plays a vital role in maintaining the stability and integrity of chromosomes, ensuring proper DNA replication, and regulating gene expression. Dysregulation of telomeric D-loop binding can have detrimental effects on cellular function and can contribute to various diseases, including cancer.'
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Proteins (3)

Compounds (3)