What are the repeating strands of DNA called?
Nucleotides in DNA strand Each DNA strand is composed of repeating nucleotides. Each nucleotide has phosphate and sugar(pentose) attached lengthwise and a nitrogenous base attached to the sugar. A nucleotide is the basic building block of nucleic acids. RNA and DNA are polymers made of long chains of nucleotides.
What is repetitive RNA?
Repetitive RNA (repRNA) sequences emerge as important regulators of the dynamic organization of genomic loci into membrane-less subcompartments with distinct nuclear functions. These domains include sites of active transcription like the nucleolus as well as (peri)centromeric and telomeric satellite repeats.
What does repeat mutation mean?
The mutation, referred to as “trinucleotide repeat (TNR) expansion,” occurs when the number of triplets present in a mutated gene is greater than the number found in a normal gene [1–3]. Additionally, the number of triplets in the disease gene continues to increase as the disease gene is inherited (Fig.
What are CTG repeats?
Abstract. A CTG repeat expansion in the DMPK gene is the causative mutation of myotonic dystrophy type 1 (DM1). Transcription of the expanded CTG repeat produces toxic gain-of-function CUG RNA, leading to disease symptoms.
What are the types of repetitive DNA?
Repetitive DNA can be divided into two classes: the tandem repetitive sequences (known as satellite DNA) and the interspersed repeats.
Why is DNA repeated?
Generic repeated signals in the DNA are necessary to format expression of unique coding sequence files and to organise additional functions essential for genome replication and accurate transmission to progeny cells.
Are pseudogenes transcribed?
Background. Transcribed pseudogenes are copies of protein-coding genes that have accumulated indicators of coding-sequence decay (such as frameshifts and premature stop codons), but nonetheless remain transcribed.
What does the nuclear matrix organize?
The matrix provides the basic shape and structure of the nucleus. In the interphase nucleus this nuclear matrix has been reported to be a central element in the organization of DNA loop domains and contains fixed sites for DNA replication and transcription.
What are the diseases that can be detected by the expansion of repeats?
Repeat expansion diseases include both causes of myotonic dystrophy (DM1 and DM2), the most common genetic cause of amyotrophic lateral sclerosis/frontotemporal dementia (C9ORF72), Huntington disease and eight other polyglutamine disorders including the most common forms of dominantly inherited ataxia, the most common …
Which of the following diseases is caused by expanding repeats mutations?
The second DNA-triplet repeat disease, fragile X-E syndrome, was also identified on the X chromosome, but was found to be the result of an expanded CCG repeat….Polyglutamine (PolyQ) diseases.
| Type | SCA17 (Spinocerebellar ataxia Type 17) |
|---|---|
| Gene | TBP |
| Normal PolyQ repeats | 25 – 42 |
| Pathogenic PolyQ repeats | 47 – 63 |
What is DM1 and DM2?
Congenital DM1 is characterized by muscle weakness (hypotonia), difficulty breathing, intellectual disability and early death. DM type 2 (DM2) causes similar symptoms to DM1, but is generally a less severe disorder and does not cause congenital disease. DM1 is caused by an alteration in the DMPK gene.
What is CTG disease?
Trinucleotide repeat disorders, also known as microsatellite expansion diseases, are a set of over 50 genetic disorders caused by trinucleotide repeat expansion, a kind of mutation in which repeats of three nucleotides (trinucleotide repeats) increase in copy numbers until they cross a threshold above which they become …
What are repeat RNAs and how do they work?
Repeat RNAs associate with replication forks and post-replicative DNA Noncoding RNA has a proven ability to direct and regulate chromatin modifications by acting as scaffolds between DNA and histone-modifying complexes.
How do repeat-containing RNAs contribute to pathogenic RNA gain-of-function mechanisms?
Despite variant nucleotide content, number of consecutive repeats, and different locations in the genome, many of these diseases have pathogenic RNA gain-of-function mechanisms. The repeat-containing RNAs can form structures in vitro predicted to contribute to the disease through assembly of intracellular RNA aggregates termed foci.
How do expanded repeat RNAs affect alternative splicing?
The expanded repeat RNAs within these foci sequester RNA binding proteins (RBPs) with important roles in the regulation of RNA metabolism, most notably alternative splicing (AS). These deleterious interactions lead to downstream alterations in transcriptome-wide AS directly linked with disease symptoms.
Does ncRNA play a role in DNA replication and epigenome maintenance?
Noncoding RNA has a proven ability to direct and regulate chromatin modifications by acting as scaffolds between DNA and histone-modifying complexes. However, it is unknown if ncRNA plays any role in DNA replication and epigenome maintenance, including histone eviction and reinstallment of histone m …