MORN1 containing repeat 1, also known as Morn1, 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 ''MORN1''

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 ...

. The function of Morn1 is not yet well understood.

Orthologs Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a spec ...

have been found in

eukaryotes The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of ...

and

bacteria Bacteria (; : bacterium) are ubiquitous, mostly free-living organisms often consisting of one Cell (biology), biological cell. They constitute a large domain (biology), domain of Prokaryote, prokaryotic microorganisms. Typically a few micr ...

Gene

The MORN1 gene is located on

chromosome 1 Chromosome 1 is the designation for the largest human chromosome. Humans have two copies of chromosome 1, as they do with all of the autosomes, which are the non-sex chromosomes. Chromosome 1 spans about 249 million nucleotide base pairs, which a ...

at locus 1p36.33 and contains 7 MORN repeats. It has 1641 base pairs in 14 exons in the reference sequence

mRNA In molecular biology, messenger ribonucleic acid (mRNA) is a single-stranded molecule of RNA that corresponds to the genetic sequence of a gene, and is read by a ribosome in the process of Protein biosynthesis, synthesizing a protein. mRNA is ...

transcript. Genomic Context

MORN1 is nearby the SKI gene which encodes the

SKI protein The SKI protein is a nuclear Oncogene#Proto-oncogene, proto-oncogene that is associated with tumors at high cellular concentrations. SKI has been shown to interfere with normal cellular functioning by both directly impeding gene expression, expr ...

, LOC100129534, and RER1 gene on the positive strand of chromosome 1. On the minus strand, the PEX10 gene occurs further upstream of Morn1.

Alternative splicing

MORN1 contains 19 different GT-AG

intron An intron is any nucleotide sequence within a gene that is not expressed or operative in the final RNA product. The word ''intron'' is derived from the term ''intragenic region'', i.e., a region inside a gene."The notion of the cistron .e., gen ...

s, and 15 different mRNAs; 11 of which are produced by alternative splicing and 4 of which are unspliced. Of these variants there are 4 probable alternative promoters, 9 non-overlapping alternative last exons and 6 alternative

polyadenylation Polyadenylation is the addition of a poly(A) tail to an RNA transcript, typically a messenger RNA (mRNA). The poly(A) tail consists of multiple adenosine monophosphates; in other words, it is a stretch of RNA that has only adenine bases. In euka ...

sites. 753 of this gene are antisense (on + strand) to spliced SKI gene, and 193 to RER1 which may contribute to regulation of expression of itself or of its flanking genes.

Protein

The MORN1 gene encodes a protein of 497

amino acid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although over 500 amino acids exist in nature, by far the most important are the 22 α-amino acids incorporated into proteins. Only these 22 a ...

s and contains two overlapping conserved

protein domains In molecular biology, a protein domain is a region of a protein's polypeptide chain that is self-stabilizing and that folds independently from the rest. Each domain forms a compact folded three-dimensional structure. Many proteins consist of se ...

. The first is the MORN repeat region in which the protein contains 7 MORN repeats (at residues 38-211) belonging to

protein family A protein family is a group of evolutionarily related proteins. In many cases, a protein family has a corresponding gene family, in which each gene encodes a corresponding protein with a 1:1 relationship. The term "protein family" should not be ...

: pfam02493. The second is a multidomain uncharacterized protein conserved in bacteria: COG4642 which contains the MORN repeat region plus the beginning target sequence (1–211). The other 286 amino acids are less conserved among orthologs (especially distant orthologs) and belong to no known protein family. The unmodified protein is predicted to have a molecular weight of 53,835.05 daltons and an isoelectric point of 6.673. The protein has no long

hydrophobic In chemistry, hydrophobicity is the chemical property of a molecule (called a hydrophobe) that is seemingly repelled from a mass of water. In contrast, hydrophiles are attracted to water. Hydrophobic molecules tend to be nonpolar and, thu ...

regions, suggesting it is not a transmembrane protein.; It has been predicted to be localized in the cytoplasm, the nucleus or mitochondrial. The genomic context may not necessarily infer function, but Morn1 has been predicted to contain a second

peroxisomal targeting signal In biochemical protein targeting, a peroxisomal targeting signal (PTS) is a region of the peroxisomal protein that receptors recognize and bind to. It is responsible for specifying that proteins containing this motif are localised to the peroxi ...

using PSORTII at residues 451: RLPPAFKHL, which may suggest interaction with PEX10 (see genomic context above). Morn1 was also predicted to contain a

nuclear export signal A nuclear export signal (NES) is a short target peptide containing 4 hydrophobic residues in a protein that targets it for export from the cell nucleus to the cytoplasm through the nuclear pore complex using nuclear transport. It has the opposit ...

near the end of the protein at amino-acids LELH 334–338 (non-MORN repeat-containing region).

Post-translational modification

Morn1 was predicted to have several

glycosylation Glycosylation is the reaction in which a carbohydrate (or ' glycan'), i.e. a glycosyl donor, is attached to a hydroxyl or other functional group of another molecule (a glycosyl acceptor) in order to form a glycoconjugate. In biology (but not ...

sites at the

Serine Serine (symbol Ser or S) is an α-amino acid that is used in the biosynthesis of proteins. It contains an α- amino group (which is in the protonated − form under biological conditions), a carboxyl group (which is in the deprotonated − ...

488 and at

Threonine Threonine (symbol Thr or T) is an amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated −NH form when dissolved in water), a carboxyl group (which is in the deprotonated −COO− ...

residues. There were also conserved Serine, Tyrosine and Threonine residues that were predicted

Phosphorylation In biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols: : This equation can be writ ...

sites that were conserved among orthologs. See image of the Multiple Sequence alignment and Texshade.

MORN

The Membrane Occupation and Recognition Nexus is a repeat that is found in multiple copies in several proteins including junctophilins. A MORN-repeat protein has been identified in the parasite ''

Toxoplasma gondii ''Toxoplasma gondii'' () is a species of parasitic alveolate that causes toxoplasmosis. Found worldwide, ''T. gondii'' is capable of infecting virtually all warm-blooded animals, but members of the cat family (felidae) are the only known d ...

'' and other

apicomplexa The Apicomplexa (also called Apicomplexia; single: apicomplexan) are organisms of a large phylum of mainly parasitic alveolates. Most possess a unique form of organelle structure that comprises a type of non-photosynthetic plastid called an ap ...

protist A protist ( ) or protoctist is any eukaryotic organism that is not an animal, land plant, or fungus. Protists do not form a natural group, or clade, but are a paraphyletic grouping of all descendants of the last eukaryotic common ancest ...

s. In ''T. gondii'', MORN1 plays role in nuclear division and daughter cell

budding Budding or blastogenesis is a type of asexual reproduction in which a new organism develops from an outgrowth or bud due to cell division at one particular site. For example, the small bulb-like projection coming out from the yeast cell is kno ...

. It is specifically associated with the spindle poles, the anterior and interior rings of the inner membrane complex during

asexual reproduction Asexual reproduction is a type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring that arise by asexual reproduction from either unicellular or multicellular organisms inherit the f ...

sexual reproduction Sexual reproduction is a type of reproduction that involves a complex life cycle in which a gamete ( haploid reproductive cells, such as a sperm or egg cell) with a single set of chromosomes combines with another gamete to produce a zygote tha ...

; budding; and schizogony (see Apicomplexan cellular morphology). Over-expression of MORN1 resulted in specific, severe defects in nuclear segregation and daughter cell formation. It was hypothesized that “Morn1 functions as a linker protein between certain membrane regions and the parasite's cytoskeleton.” The Morn repeats are not identical, but follow a general pattern of beginning with a YeG sequence, and specifically the subsequent

glycine Glycine (symbol Gly or G; ) is an amino acid that has a single hydrogen atom as its side chain. It is the simplest stable amino acid. Glycine is one of the proteinogenic amino acids. It is encoded by all the codons starting with GG (G ...

residues are well conserved even within microbial orthologs which may suggest that the glycine residues may be important and/or involved in some structural function of the protein.

Tissue distribution

Expressed Sequence Tag In genetics, an expressed sequence tag (EST) is a short sub-sequence of a cDNA sequence. ESTs may be used to identify gene transcripts, and were instrumental in gene discovery and in gene-sequence determination. The identification of ESTs has pro ...

and

microarray A microarray is a multiplex (assay), multiplex lab-on-a-chip. Its purpose is to simultaneously detect the expression of thousands of biological interactions. It is a two-dimensional array on a Substrate (materials science), solid substrate—usu ...

data suggests that Morn1 is expressed predominantly in the

brain The brain is an organ (biology), organ that serves as the center of the nervous system in all vertebrate and most invertebrate animals. It consists of nervous tissue and is typically located in the head (cephalization), usually near organs for ...

eyes An eye is a sensory organ that allows an organism to perceive visual information. It detects light and converts it into electro-chemical impulses in neurons (neurones). It is part of an organism's visual system. In higher organisms, the ey ...

lungs The lungs are the primary organs of the respiratory system in many animals, including humans. In mammals and most other tetrapods, two lungs are located near the backbone on either side of the heart. Their function in the respiratory syste ...

parathyroid Parathyroid glands are small endocrine glands in the neck of humans and other tetrapods. Humans usually have four parathyroid glands, located on the back of the thyroid gland in variable locations. The parathyroid gland produces and secretes pa ...

salivary gland The salivary glands in many vertebrates including mammals are exocrine glands that produce saliva through a system of ducts. Humans have three paired major salivary glands ( parotid, submandibular, and sublingual), as well as hundreds of min ...

testis A testicle or testis ( testes) is the gonad in all male bilaterians, including humans, and is Homology (biology), homologous to the ovary in females. Its primary functions are the production of sperm and the secretion of Androgen, androgens, p ...

kidney In humans, the kidneys are two reddish-brown bean-shaped blood-filtering organ (anatomy), organs that are a multilobar, multipapillary form of mammalian kidneys, usually without signs of external lobulation. They are located on the left and rig ...

trachea The trachea (: tracheae or tracheas), also known as the windpipe, is a cartilaginous tube that connects the larynx to the bronchi of the lungs, allowing the passage of air, and so is present in almost all animals' lungs. The trachea extends from ...

, and to a lesser extent the

ovaries The ovary () is a gonad in the female reproductive system that produces ova; when released, an ovum travels through the fallopian tube/oviduct into the uterus. There is an ovary on the left and the right side of the body. The ovaries are endocr ...

prostate The prostate is an male accessory gland, accessory gland of the male reproductive system and a muscle-driven mechanical switch between urination and ejaculation. It is found in all male mammals. It differs between species anatomically, chemica ...

thymus The thymus (: thymuses or thymi) is a specialized primary lymphoid organ of the immune system. Within the thymus, T cells mature. T cells are critical to the adaptive immune system, where the body adapts to specific foreign invaders. The thymus ...

and the

. It is expressed in adults and in fetuses. By health state, Morn1 appears to be expressed in the normal state, as well as germ cell and kidney tumors.

Orthologs

The orthologs of the Morn1 protein are listed below obtained by BLAST analysis. The conservation of this protein is conserved in mammals and invertebrates. Reptiles, insects and birds do not seem to show much conservation of this protein while bacteria and protists show similar conservation as in birds and reptiles, but these organisms are much more evolutionarily distant from humans.

Structure similarity

The red molecules are identical residues with Morn1, the Yellow are conserved molecules within a MORN repeat and the blue and gray molecules are those with little to no similarity. Based on C-blast results Morn1 has a sequence similarity to that of Chain A, of

histone methyltransferase Histone methyltransferases (HMT) are histone-modifying enzymes (e.g., histone-lysine N-methyltransferases and histone-arginine N-methyltransferases), that catalyze the transfer of one, two, or three methyl groups to lysine and arginine residues of ...

Set79. Morn1 aligns with 77 amino acids of this chain from residues 81–158.