Treacle protein is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''TCOF1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
.
This gene encodes a nucleolar protein with an LIS1 homology domain. The protein is involved in ribosomal DNA gene transcription through its interaction with
upstream binding factor
In molecular biology, a transcription factor (TF) (or sequence-specific DNA-binding factor) is a protein that controls the rate of transcription of genetic information from DNA to messenger RNA, by binding to a specific DNA sequence. The fu ...
(UBF). Mutations in this gene have been associated with
Treacher Collins syndrome
Treacher Collins syndrome (TCS) is a genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. The degree to which a person is affected, however, may vary from mild to severe. Complications may include breathing prob ...
, a disorder which includes abnormal craniofacial development. Alternate transcriptional splice variants encoding different isoforms have been found for this gene, but only three of them have been characterized to date.
TCOF1 is a
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
that provides instructions for making a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
called treacle. This protein is active during early embryonic development in structures that become
bone
A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
s and other tissues in the face. Although the precise function of this protein is unknown, researchers believe that it plays a critical role in the development of facial bones and related structures.
Studies suggest that treacle is involved in the production of a molecule called
ribosomal RNA
Ribosomal ribonucleic acid (rRNA) is a type of non-coding RNA which is the primary component of ribosomes, essential to all cells. rRNA is a ribozyme which carries out protein synthesis in ribosomes. Ribosomal RNA is transcribed from ribosomal ...
(rRNA) within cells. Treacle is active in the
nucleolus
The nucleolus (, plural: nucleoli ) is the largest structure in the nucleus of eukaryotic cells. It is best known as the site of ribosome biogenesis, which is the synthesis of ribosomes. The nucleolus also participates in the formation of sig ...
, which is a small region inside the
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
*Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucle ...
where rRNA is produced. As a major component of cell structures called
ribosome
Ribosomes ( ) are macromolecular machines, found within all cells, that perform biological protein synthesis (mRNA translation). Ribosomes link amino acids together in the order specified by the codons of messenger RNA (mRNA) molecules to ...
s, rRNA is essential for the assembly of proteins.
Aside from its interaction with UBF, treacle has been implicated in the
methylation
In the chemical sciences, methylation denotes the addition of a methyl group on a substrate, or the substitution of an atom (or group) by a methyl group. Methylation is a form of alkylation, with a methyl group replacing a hydrogen atom. These t ...
of the precursor to mature ribosomal RNA by interaction with the nucleolar protein pNop56.
The TCOF1 gene is located on the long (q) arm of
chromosome 5
Chromosome 5 is one of the 23 pairs of chromosomes in humans. People normally have two copies of this chromosome. Chromosome 5 spans about 181 million base pairs (the building blocks of DNA) and represents almost 6% of the total DNA in cells. C ...
between positions 32 and 33.1, from
base pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
149,717,427 to base pair 149,760,047.
Related diseases
More than 120
mutation
In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...
s in the TCOF gene have been identified in people with
Treacher Collins syndrome
Treacher Collins syndrome (TCS) is a genetic disorder characterized by deformities of the ears, eyes, cheekbones, and chin. The degree to which a person is affected, however, may vary from mild to severe. Complications may include breathing prob ...
. Most of these mutations insert or delete a small number of
DNA building blocks (
base pair
A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...
s) in the TCOF1 gene. TCOF1 mutations lead to the production of an abnormally small, nonfunctional version of treacle or prevent the cell from producing this protein. Researchers speculate that a loss of treacle reduces the production of rRNA in parts of the
embryo
An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...
that develop into facial bones and tissues. It is not known how loss of the treacle protein causes the specific problems with facial development found in Treacher Collins syndrome. For instance, mutations in the TCOF gene of these individuals often result in a
cleft palate
A cleft lip contains an opening in the upper lip that may extend into the nose. The opening may be on one side, both sides, or in the middle. A cleft palate occurs when the palate (the roof of the mouth) contains an opening into the nose. The te ...
.
[Dixon MJ, Marazita ML, Beaty TH, Murray JC (2011). "Cleft lip and palate: understanding genetic and environmental influences". Nature Reviews Genetics (12): 167-178.]
Model organisms
Mutations in this gene in
Jindo dogs have been associated to the observed cranial differences between Jindo and
boxer Boxer most commonly refers to:
* Boxer (boxing), a competitor in the sport of boxing
*Boxer (dog), a breed of dog
Boxer or boxers may also refer to:
Animal kingdom
* Boxer crab
* Boxer shrimp, a small group of decapod crustaceans
* Boxer snipe ee ...
dogs.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Treacher Collins Syndrome or Mandibulofacial DysostosisGeneCard*
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{{DEFAULTSORT:Treacle Protein