Ly6/neurotoxin 1 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 ...
in humans that is encoded by the ''LYNX1''
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 ...
.
Alternatively spliced
Alternative splicing, alternative RNA splicing, or differential splicing, is an alternative RNA splicing, splicing process during gene expression that allows a single gene to produce different splice variants. For example, some exons of a gene ma ...
variants encoding different isoforms have been identified.
Function
This gene encodes a member of the Ly-6/
neurotoxin
Neurotoxins are toxins that are destructive to nervous tissue, nerve tissue (causing neurotoxicity). Neurotoxins are an extensive class of exogenous chemical neurological insult (medical), insultsSpencer 2000 that can adversely affect function ...
gene family, a group of
lymphocyte
A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), an ...
antigens that attach to the cell surface by a
glycosylphosphatidylinositol
Glycosylphosphatidylinositol () or glycophosphatidylinositol (GPI) is a phosphoglyceride that can be attached to the C-terminus of a protein during posttranslational modification. The resulting GPI-anchored proteins play key roles in a wide vari ...
anchor and have a unique structure showing conserved 8-10 cysteine residues with a characteristic spacing pattern. Functional analysis indicates that this protein is not a ligand or neurotransmitter but has the capacity to enhance
nicotinic acetylcholine receptor
Nicotinic acetylcholine receptors, or nAChRs, are Receptor (biochemistry), receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the c ...
function in the presence of acetylcholine. This gene may also play a role in the
pathogenesis
In pathology, pathogenesis is the process by which a disease or disorder develops. It can include factors which contribute not only to the onset of the disease or disorder, but also to its progression and maintenance. The word comes .
Descript ...
of
psoriasis vulgaris
Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete body ...
.
The LYNX1 gene codes for a protein (Lynx1) that binds to
acetylcholine receptor
An acetylcholine receptor (abbreviated AChR) or a cholinergic receptor is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.
Classification
Like other transmembrane receptors, acetylcholine receptor ...
s in the brain.
Lynx1 a member of the Ly6 superfamily of proteins that are capable of modulating neurotransmitter receptors.
Lynx1 and Visual Plasticity
Transgenic mice
A genetically modified mouse, genetically engineered mouse model (GEMM) or transgenic mouse is a mouse (''Mus musculus'') that has had its genome altered through the use of genetic engineering techniques. Genetically modified mice are commonly use ...
without Lynx1 expression do not have a normal
critical period
In developmental psychology and developmental biology, a critical period is a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli. If, for some reason, the org ...
of
neuroplasticity
Neuroplasticity, also known as neural plasticity or just plasticity, is the ability of neural networks in the brain to change through neurogenesis, growth and reorganization. Neuroplasticity refers to the brain's ability to reorganize and rewir ...
in the
visual cortex
The visual cortex of the brain is the area of the cerebral cortex that processes visual information. It is located in the occipital lobe. Sensory input originating from the eyes travels through the lateral geniculate nucleus in the thalam ...
for development of
ocular dominance column Ocular dominance columns are stripes of neurons in the visual cortex of certain mammals (including humans) that respond preferentially to input from one eye or the other. The columns span multiple cortical layers, and are laid out in a striped pa ...
s.
These mice show unusually rapid recovery from
amblyopia
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amb ...
in adulthood indicating a role in reduction of
synaptic plasticity during the normal expression of Lynx1 in adult brain.
Lynx1 reduces adult visual cortex
plasticity
Plasticity may refer to:
Science
* Plasticity (physics), in engineering and physics, the propensity of a solid material to undergo permanent deformation under load
* Behavioral plasticity, change in an organism's behavior in response to exposur ...
by binding to
nicotinic acetylcholine receptors
Nicotinic acetylcholine receptors, or nAChRs, are receptor polypeptides that respond to the neurotransmitter acetylcholine. Nicotinic receptors also respond to drugs such as the agonist nicotine. They are found in the central and peripheral ner ...
(NAchR) and diminishing
acetylcholine
Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...
signaling.
After the developmental
critical period
In developmental psychology and developmental biology, a critical period is a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli. If, for some reason, the org ...
and into adulthood, both Lynx1 mRNA and protein levels increase in the adult V1 and the
lateral geniculate nucleus
In neuroanatomy, the lateral geniculate nucleus (LGN; also called the lateral geniculate body or lateral geniculate complex) is a structure in the thalamus and a key component of the mammalian visual pathway. It is a small, ovoid, Anatomical ter ...
(LGN).
Lynx1 and nAChR mRNAs are co-expressed in the LGN, as well as in
parvalbumin
Parvalbumin (PV) is a calcium-binding protein with low molecular weight (typically 9–11 kDa). In humans, it is encoded by the ''PVALB'' gene. It is a member of the albumin family; it is named for its size (''parv-'', from Latin ' which means " ...
-positive
GABAergic
In molecular biology and physiology, something is GABAergic or GABAnergic if it pertains to or affects the neurotransmitter gamma-aminobutyric acid (GABA). For example, a synapse is GABAergic if it uses GABA as its neurotransmitter, and a GABAergic ...
interneurons.
After monocular deprivation during the
critical period
In developmental psychology and developmental biology, a critical period is a maturational stage in the lifespan of an organism during which the nervous system is especially sensitive to certain environmental stimuli. If, for some reason, the org ...
to induce
amblyopia
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amb ...
, Lynx1 knock-out rat models spontaneously recovered normal visual acuity by reopening the closed eye.
Similarly, an infusion of
physostigmine
Physostigmine (also known as eserine from ''éséré'', the West African name for the Calabar bean) is a highly toxic parasympathomimetic alkaloid, specifically, a reversible cholinesterase inhibitor. It occurs naturally in the Calabar bean and ...
to increase
acetylcholine
Acetylcholine (ACh) is an organic compound that functions in the brain and body of many types of animals (including humans) as a neurotransmitter. Its name is derived from its chemical structure: it is an ester of acetic acid and choline. Par ...
signaling prompted recovery from
amblyopia
Amblyopia, also called lazy eye, is a disorder of sight in which the brain fails to fully process input from one eye and over time favors the other eye. It results in decreased vision in an eye that typically appears normal in other aspects. Amb ...
in wild type mice
Inhibition of Lynx1 may be a possible therapeutic mechanism to prolong
synaptic plasticity
In neuroscience, synaptic plasticity is the ability of synapses to Chemical synapse#Synaptic strength, strengthen or weaken over time, in response to increases or decreases in their activity. Since memory, memories are postulated to be represent ...
of the visual cortex and improve binocular function of some
amblyopes.
See also
Other Ly6 family proteins that are expressed in the brain:
Lynx2,
LYPD6,
LYPD6B and
PSCA.
References
{{NLM content
Genes on human chromosome 8