Ly6/neurotoxin 1 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, res ...
in humans that is encoded by the ''LYNX1''
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 b ...
.
Alternatively spliced
Alternative splicing, or alternative RNA splicing, or differential splicing, is an alternative splicing process during gene expression that allows a single gene to code for multiple proteins. In this process, particular exons of a gene may be ...
variants encoding different isoforms have been identified.
Function
This gene encodes a member of the Ly-6/
neurotoxin 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 natural killer cells (which function in cell-mediated, cytotoxic innate immunity), T cells (for cell-mediated, cytotoxic ad ...
antigens that attach to the cell surface by a
glycosylphosphatidylinositol
Glycosylphosphatidylinositol (), or glycophosphatidylinositol, or GPI in short, 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 ...
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 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 ...
function in the presence of acetylcholine. This gene may also play a role in the
pathogenesis
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 from Greek πάθος ''pat ...
of
psoriasis vulgaris.
The LYNX1 gene codes for a protein (Lynx1) that binds to
acetylcholine receptor
An acetylcholine receptor (abbreviated AChR) is an integral membrane protein that responds to the binding of acetylcholine, a neurotransmitter.
Classification
Like other transmembrane receptors, acetylcholine receptors are classified according ...
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 or genetically engineered mouse model (GEMM) is a mouse (''Mus musculus'') that has had its genome altered through the use of genetic engineering techniques. Genetically modified mice are commonly used for research or ...
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 brain plasticity, is the ability of neural networks in the brain to change through growth and reorganization. It is when the brain is rewired to function in some way that differs from how it p ...
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 thalamus and ...
for development of
ocular dominance columns.
These mice show unusually rapid recovery from
amblyopia 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 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 ...
(NAchR) and diminishing
acetylcholine 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, ventral projec ...
(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 not a member of the albumin family; it is named for its size (''parv-'', from Latin ''parvus'' smal ...
-positive
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, 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 signaling prompted recovery from
amblyopia 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 strengthen or weaken over time, in response to increases or decreases in their activity. Since memories are postulated to be represented by vastly interconnected neural circuit ...
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
LY6/PLAUR Domain Containing 6B, also known under the name Cancer/Testis Antigen 116 (CTA116) and LYPD7 is encoded by the ''LYPD6B'' gene. LYPD6B is a member of the lymphocyte antigen 6 (LY6) protein family. It is expressed in the testis, lungs, ...
and
PSCA.
References
{{NLM content
Genes on human chromosome 8