Morn repeat containing 1

MORN repeat containing 1
Identifiers
Symbols	MORN1; FLJ13941
External IDs	MGI: 1924116 HomoloGene: 11757 GeneCards: MORN1 Gene
Gene Ontology Cellular component • integral to membrane Biological process • G-protein coupled receptor protein signaling pathway Sources: Amigo / QuickGO
Orthologs
Species	Human	Mouse
Entrez	79906	76866
Ensembl	ENSG00000116151	ENSMUSG00000029049
UniProt	Q5T089	A2RTS7
RefSeq (mRNA)	NM_024848	NM_001081100.1
RefSeq (protein)	NP_079124	NP_001074569.1
Location (UCSC)	Chr 1: 2.25 – 2.36 Mb	Chr 4: 154.46 – 154.52 Mb
PubMed search	[1]	[2]

MORN1 containing repeat 1, also known as Morn1, is a protein that in humans is encoded by the MORN1 gene.^[1][2]

The function of Morn1 is not yet well understood. Orthologs have been found in eukaryotes and bacteria.

Gene

The MORN1 gene is located on Chromosome 1 at locus 1p36.33 and contains 7 MORN repeats. It has 1641 base pairs in 14 exons in the reference sequence mRNA transcript.^[3]

MORN1 is nearby the SKI gene which encodes the SKI protein, 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 introns, 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 sites. 753 bps of this gene are antisense (on + strand) to spliced SKI gene, and 193 bps to RER1^[4] which may contribute to regulation of expression of itself or of its flanking genes.

Protein

There are 7 consecutive MORN repeats in the Morn1 protein

The MORN1 gene encodes a protein of 497 amino acids and contains two overlapping conserved protein domains. The first is the MORN repeat region in which the protein contains 7 MORN repeats (at residues 38-211) belonging to protein family: 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).^[5] 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 regions, suggesting it is not a transmembrane protein.^[6] It has been predicted to be localized in the cytoplasm, the nucleus or mitochondrial.^[7]

The genomic context may not necessarily infer function, but Morn1 has been predicted to contain a second peroxisomal targeting signal using PSORTII at residues 451: RLPPAFKHL,^[7] which may suggest interaction with PEX10 (see genomic context above).

Morn1 was also predicted to contain a nuclear export signal near the end of the protein at amino-acids LELH 334-338 (non-MORN repeat-containing region).^[8]

Predicted Phosphorylation (Pho)and Glycosylation(Glc) sites

Listed top to bottom: Horse, Human, Mouse, Rat and Sea Urchin

Post-translational modification

Morn1 was predicted to have several glycosylation sites at the Serine 488 and at Threonine residues.^[9] There were also conserved Serine, Tyrosine and Threonine residues that were predicted Phosphorylation sites that were conserved among orthologs.^[10] See image of the Multiple Sequence alignment and Texshade.^[11][12]

MORN

The Membrane Occupation and Recognition Nexus is a repeat is found in multiple copies in several proteins including junctophilins.^[5] A MORN-repeat protein has been identified in the parasite Toxoplasma gondii and other Apicomplexan protists.^[13]

In T. gondii, MORN1 plays role in nuclear division and daughter cell budding. It is specifically associated with the spindle poles, the anterior and interior rings of the inner membrane complex during asexual reproduction/sexual reproduction; 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.”^[14] The Morn repeats are not identical, but follow a general pattern of beginning with a YeG seqeuence, and specifically the subsequent Glycine 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 and microarray data suggests that Morn1 is expressed predominantly in the brain, eyes, lungs, parathyroid, salivary gland, testis, kidneys, trachea, and to a lesser extent the ovaries, prostate, thymus and the trachea. 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.^[15]

Orthologs

The orthologs of the Morn1 protein are listed below obtained by BLAST^[15] 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 it must be noted that these organisms are much more evolutionarily distant from humans.

Organism	Accession Number	% Identity to Human Gene
Equus caballus	XP_001495156[16]	74
Mus musculus	NP_001074569[17]	69
Canis familiaris	XP_849172[18]	69
Rattus norvegicus	NP_001005544[19]	66
Branchiostoma floridae (Lancelet)	XP_002590560.1[20]	58
Strongylocentrotus purpuratus	XP_793509.1[21]	58
Trichoplax adhaerens	XP_002113780.1[22]	50
Chlamydomonas reinhardtii	XP_001699198.1[23]	45
Xenopus Laevis (African clawed frog)	NP_001088789[24]	41
Toxoplasma gondii	XP_002364290[25]	36
Taeniopygia guttata	XP_002192069[26]	35
Gallus gallus	XP_416745[27]	33
Drosophila virilis	XP_002048955.1[28]	29
Caenorhabditis elegans	NP_492193.2[29]	22

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^[30] Morn1 has a sequence similarity to that of Chain A, of Histone methyltransferase Set79. Morn1 aligns with 77 amino acids of this chain from residues 81-158.

References

1. ^ "Entrez Gene: MORN repeat containing 1". http://www.ncbi.nlm.nih.gov/sites/entrez?Db=gene&Cmd=ShowDetailView&TermToSearch=79906. 
2. ^ Strausberg RL, Feingold EA, Grouse LH, et al. (December 2002). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=139241. 
3. ^ "NCBI GenBank Record: MORN repeat containing 1". http://www.ncbi.nlm.nih.gov/nuccore/NM_024848.1?ordinalpos=15&itool=EntrezSystem2.PEntrez.Sequence.Sequence_ResultsPanel.Sequence_RVDocSum. 
4. ^ "National Center for Biotechnology Information AceView". http://www.ncbi.nlm.nih.gov/IEB/Research/Acembly/av.cgi?exdb=AceView&db=36a&term=morn1&submit=Go. 
5. ^ ^{a b} "Conserved Domains: Conserved domains on MORN repeat-containing protein 1". http://www.ncbi.nlm.nih.gov/Structure/cdd/wrpsb.cgi?INPUT_TYPE=live&SEQUENCE=NP_079124.1. 
6. ^ Brendel V, Bucher P, Nourbakhsh IR, Blaisdell BE, Karlin S (March 1992). "Methods and algorithms for statistical analysis of protein sequences". Proc. Natl. Acad. Sci. U.S.A. 89 (6): 2002–6. doi:10.1073/pnas.89.6.2002. PMC 48584. PMID 1549558. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=48584. ; "ISREC SAPS server". http://www.isrec.isb-sib.ch/software/SAPS_form.html. 
7. ^ ^{a b} "PSORT II: Prediction of Protein Sorting Signals and Localization Sites in Amino Acid Sequences". http://psort.ims.u-tokyo.ac.jp. 
8. ^ la Cour T, Kiemer L, Mølgaard A, Gupta R, Skriver K, Brunak S (June 2004). "Analysis and prediction of leucine-rich nuclear export signals". Protein Eng. Des. Sel. 17 (6): 527–36. doi:10.1093/protein/gzh062. PMID 15314210. http://www.cbs.dtu.dk/services/NetNES/. 
9. ^ "ExPasy: YinOYang (Prediction of glycosylation sites in proteomes: from post-translational modifications to protein function. R Gupta.Ph.D. thesis at CBS, 2001.". http://www.cbs.dtu.dk/services/YinOYang/. 
10. ^ "NetPHOS: Blom, N., Gammeltoft, S., and Brunak, S. "Sequence- and structure-based prediction of eukaryotic protein phosphorylation sites." Journal of Molecular Biology: 294(5): 1351-1362, 1999.". http://www.cbs.dtu.dk/services/NetPhos/. 
11. ^ "CLUSTAL W: Julie D. Thompson, Desmond G. Higgins and Toby J. Gibson". http://www.ebi.ac.uk/Tools/clustalw2/index.html. 
12. ^ "TeXshade version 1.4, by Eric Beitz". http://homepages.uni-tuebingen.de/beitz/txe.html. 
13. ^ Ferguson DJ, Sahoo N, Pinches RA, Bumstead JM, Tomley FM, Gubbels MJ (April 2008). "MORN1 has a conserved role in asexual and sexual development across the apicomplexa". Eukaryotic Cell 7 (4): 698–711. doi:10.1128/EC.00021-08. PMC 2292627. PMID 18310354. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2292627. 
14. ^ Gubbels MJ, Vaishnava S, Boot N, Dubremetz JF, Striepen B (June 2006). "A MORN-repeat protein is a dynamic component of the Toxoplasma gondii cell division apparatus". J. Cell. Sci. 119 (Pt 11): 2236–45. doi:10.1242/jcs.02949. PMID 16684814. 
15. ^ ^{a b} "Genecards: Expression Data Morn1". http://www.genecards.org/cgi-bin/carddisp.pl?gene=MORN1&search=morn1. 
16. ^ http://www.ncbi.nlm.nih.gov/protein/XP_001495156.1
17. ^ http://www.ncbi.nlm.nih.gov/protein/124487378
18. ^ http://www.ncbi.nlm.nih.gov/protein/73956615
19. ^ http://www.ncbi.nlm.nih.gov/protein/53850616
20. ^ http://www.ncbi.nlm.nih.gov/protein/260791063
21. ^ http://www.ncbi.nlm.nih.gov/protein/72042624
22. ^ http://www.ncbi.nlm.nih.gov/protein/196007828
23. ^ http://www.ncbi.nlm.nih.gov/protein/159482278
24. ^ http://www.ncbi.nlm.nih.gov/protein/147901904
25. ^ http://www.ncbi.nlm.nih.gov/protein/237829985
26. ^ http://www.ncbi.nlm.nih.gov/protein/224070490
27. ^ http://www.ncbi.nlm.nih.gov/protein/50730001
28. ^ http://www.ncbi.nlm.nih.gov/protein/1953803931
29. ^ http://www.ncbi.nlm.nih.gov/protein/25149766
30. ^ "NCBI: Cblast". http://www.ncbi.nlm.nih.gov/Structure/cblast/cblast.cgi?client=entrez&query_gi=13376267&hit=27065098&hsp=1&output=html&pagenum=1&epp=20&sort=evalue&view=graphic&subset=lowrdn. 

Further reading

• Strausberg RL, Feingold EA, Grouse LH, et al. (2002). "Generation and initial analysis of more than 15,000 full-length human and mouse cDNA sequences.". Proc. Natl. Acad. Sci. U.S.A. 99 (26): 16899–903. doi:10.1073/pnas.242603899. PMC 139241. PMID 12477932. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=139241. 
• Gerhard DS, Wagner L, Feingold EA, et al. (2004). "The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC).". Genome Res. 14 (10B): 2121–7. doi:10.1101/gr.2596504. PMC 528928. PMID 15489334. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=528928. 
• Gregory SG, Barlow KF, McLay KE, et al. (2006). "The DNA sequence and biological annotation of human chromosome 1.". Nature 441 (7091): 315–21. doi:10.1038/nature04727. PMID 16710414. 
• Ota T, Suzuki Y, Nishikawa T, et al. (2004). "Complete sequencing and characterization of 21,243 full-length human cDNAs.". Nat. Genet. 36 (1): 40–5. doi:10.1038/ng1285. PMID 14702039.