RPL38
Encyclopedia
60S ribosomal protein L38 is a protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

 that in humans is encoded by the RPL38 gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

.

Gene

The human RPL38 gene resides on the long arm of chromosome
Chromosome
A chromosome is an organized structure of DNA and protein found in cells. It is a single piece of coiled DNA containing many genes, regulatory elements and other nucleotide sequences. Chromosomes also contain DNA-bound proteins, which serve to package the DNA and control its functions.Chromosomes...

 17 at 17q25.1. It consists of five exons spread out over a distance of 6223 bp. The 213 nucleotide open reading frame encodes a 70 amino acid protein
Protein
Proteins are biochemical compounds consisting of one or more polypeptides typically folded into a globular or fibrous form, facilitating a biological function. A polypeptide is a single linear polymer chain of amino acids bonded together by peptide bonds between the carboxyl and amino groups of...

. Alternative splice variants have been identified, both encoding the same protein. As is typical for genes encoding ribosomal proteins, there are multiple processed pseudogene
Pseudogene
Pseudogenes are dysfunctional relatives of known genes that have lost their protein-coding ability or are otherwise no longer expressed in the cell...

s of this gene dispersed through the genome, including one located in the promoter region of the angiotensin II receptor type 1
Angiotensin II receptor type 1
Angiotensin II receptor, type 1 or AT1 receptor is an angiotensin receptor. It has vasopressor effects and regulates aldosterone secretion. It is an important effector controlling blood pressure and volume in the cardiovascular system...

 gene.

Function

Ribosome
Ribosome
A ribosome is a component of cells that assembles the twenty specific amino acid molecules to form the particular protein molecule determined by the nucleotide sequence of an RNA molecule....

s, the organelles that catalyze protein synthesis, consist of a small 40S
40S
40S is the small subunit of eukaryotic ribosomes.It interacts with the internal ribosome entry site of the hepatitis C virus.The following is a list of proteins contained in the 40S ribosome:...

 subunit and a large 60S
60S
60S is the large ribosomal subunit in eukaryotes. It corresponds to 50S in prokaryotes.It consists of the following:* 5S* 28S* 5.8SThe following is a list of proteins contained within the 60S ribosome:...

 subunit. Together these subunits are composed of 4 RNA species and approximately 80 structurally distinct proteins. This gene encodes a ribosomal protein that is a component of the 60S subunit. The protein belongs to the L38E family of ribosomal proteins. It is located in the cytoplasm
Cytoplasm
The cytoplasm is a small gel-like substance residing between the cell membrane holding all the cell's internal sub-structures , except for the nucleus. All the contents of the cells of prokaryote organisms are contained within the cytoplasm...

.

Genetics

An ~18kbp deletion, encompassing the entire Rpl38 locus
Locus (genetics)
In the fields of genetics and genetic computation, a locus is the specific location of a gene or DNA sequence on a chromosome. A variant of the DNA sequence at a given locus is called an allele. The ordered list of loci known for a particular genome is called a genetic map...

 underlies the phenotype
Phenotype
A phenotype is an organism's observable characteristics or traits: such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior...

 in the Tail-short (Ts) mutant mouse. In homozygous state, Ts mice die at around 3–4 days of gestation
Gestation
Gestation is the carrying of an embryo or fetus inside a female viviparous animal. Mammals during pregnancy can have one or more gestations at the same time ....

. Ts/+ heterozygous embryos undergo an anemia
Anemia
Anemia is a decrease in number of red blood cells or less than the normal quantity of hemoglobin in the blood. However, it can include decreased oxygen-binding ability of each hemoglobin molecule due to deformity or lack in numerical development as in some other types of hemoglobin...

 and develop skeletal malformations. During the perinatal period ~30% of the heterozygotes die. The surviving heterozygous Ts exhibit great variations of shortened, kinked and otherwise malformed tails. They also weigh less than their wild-type littermates but have otherwise a normal life span. Additionally, Ts mice develop a conductive hearing loss
Conductive hearing loss
Conductive hearing loss occurs when there is a problem conducting sound waves anywhere along the route through the outer ear, tympanic membrane , or middle ear ....

 shortly after the onset of hearing at around 3–4 weeks of age. The hearing loss is the result of ectopic ossification
Ossification
Ossification is the process of laying down new bone material by cells called osteoblasts. It is synonymous with bone tissue formation...

 along the round window ridge at the outside of the cochlea
Cochlea
The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....

, massive deposition of cholesterol crystals in the middle ear cavity
Middle ear
The middle ear is the portion of the ear internal to the eardrum, and external to the oval window of the cochlea. The mammalian middle ear contains three ossicles, which couple vibration of the eardrum into waves in the fluid and membranes of the inner ear. The hollow space of the middle ear has...

, an enlarged Eustachian tube
Eustachian tube
The Eustachian tube is a tube that links the nasopharynx to the middle ear. It is a part of the middle ear. In adult humans the Eustachian tube is approximately 35 mm long. It is named after the sixteenth-century anatomist Bartolomeo Eustachi...

 and a chronic otitis media
Otitis media
Otitis media is inflammation of the middle ear, or a middle ear infection.It occurs in the area between the tympanic membrane and the inner ear, including a duct known as the eustachian tube. It is one of the two categories of ear inflammation that can underlie what is commonly called an earache,...

 with effusion.

In Drosophila melanogaster
Drosophila melanogaster
Drosophila melanogaster is a species of Diptera, or the order of flies, in the family Drosophilidae. The species is known generally as the common fruit fly or vinegar fly. Starting from Charles W...

, loss-of-function alleles of RPL38, cause embryonic lethality in homozygotes and protracted growth and shortened bristles in heterozygotes. Due to the haplo-insufficient nature of the mutation, the phenotype is inherited as a dominant trait.

In humans, mutations in ribosomal proteins cause Diamond-Blackfan Anemia
Diamond-Blackfan anemia
Diamond–Blackfan anemia , also known as Blackfan–Diamond anemia and Inherited erythroblastopenia, is a congenital erythroid aplasia that usually presents in infancy. DBA patients have low red blood cell counts . The rest of their blood cells are normal...

. However, no disease has yet been linked to mutations in human RPL38.
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