H/ACA ribonucleoprotein complex subunit 4 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
''DKC1''.
Dyskerin is a
pseudouridine
Pseudouridine (5-ribosyluracil, abbreviated by the Greek letter psi- Ψ) is an isomer of the nucleoside uridine in which the uracil is attached via a carbon-carbon instead of a nitrogen-carbon glycosidic bond.
Pseudouridine is the most abundant ...
synthase
In biochemistry, a synthase is an enzyme that catalyses a synthesis process.
Note that, originally, biochemical nomenclature distinguished synthetases and synthases. Under the original definition, synthases do not use energy from nucleoside trip ...
enzyme which is part of the TruB family of enzymes.
Dyskerin is an L-shaped protein of 514 residues and a molecular weight of about 58
kilo-
Kilo is a decimal prefix, decimal metric prefix, unit prefix in the metric system denoting multiplication by one thousand (103). It is used in the International System of Units, where it has the symbol k, in Letter case, lowercase.
The prefix ' ...
daltons.
Dyskerin is essential for the activity of
telomerase
Telomerase, also called terminal transferase, is a ribonucleoprotein that adds a species-dependent telomere repeat sequence to the 3' end of telomeres. A telomere is a region of repetitive sequences at each end of the chromosomes of most euka ...
by accumulating
telomerase RNA component
Telomerase RNA component, also known as TR, TER or TERC, is an Non-coding RNA, ncRNA found in eukaryotes that is a component of telomerase, the enzyme used to extend telomeres. TERC serves as a template for telomere DNA replication, replicati ...
(TERC).
This gene is a member of the
H/ACA snoRNPs (small nucleolar ribonucleoproteins) gene family. snoRNPs are involved in various aspects of rRNA processing and modification and have been classified into two families: C/D and H/ACA. The H/ACA snoRNPs also include the NOLA1, 2 and 3 proteins. The protein encoded by this gene and the three NOLA proteins localize to the dense fibrillar components of nucleoli and to coiled
(Cajal) bodies in the nucleus. Both 18S
rRNA
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 ...
production and rRNA pseudouridylation are impaired if any one of the four proteins is depleted. The protein encoded by this gene is related to the ''
Saccharomyces cerevisiae
''Saccharomyces cerevisiae'' () (brewer's yeast or baker's yeast) is a species of yeast (single-celled fungal microorganisms). The species has been instrumental in winemaking, baking, and brewing since ancient times. It is believed to have be ...
'' Cbf5p and ''
Drosophila melanogaster
''Drosophila melanogaster'' is a species of fly (an insect of the Order (biology), order Diptera) in the family Drosophilidae. The species is often referred to as the fruit fly or lesser fruit fly, or less commonly the "vinegar fly", "pomace fly" ...
'' Nop60B proteins. The gene lies in a tail-to-tail orientation with the palmitoylated erythrocyte membrane protein (MPP1) gene and is transcribed in a telomere to centromere direction. Both nucleotide substitutions and single trinucleotide repeat polymorphisms have been found in this gene. Mutations in this gene cause X-linked
dyskeratosis congenita
Dyskeratosis congenita (DKC), also known as Zinsser-Engman-Cole syndrome, is a rare progressive congenital disorder with a highly variable phenotype. The entity was classically defined by the triad of abnormal skin pigmentation, nail dystrophy, an ...
.
Clinical significance
Mutations in ''DKC1'' are associated to
Hoyeraal-Hreidarsson syndrome.
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on Dyskeratosis Congenita
Telomere-related genes
Telomere-related proteins
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