SYNB_MOUSE
ID SYNB_MOUSE Reviewed; 618 AA.
AC Q8BI41; V9GXQ5;
DT 07-JUN-2017, integrated into UniProtKB/Swiss-Prot.
DT 01-MAR-2003, sequence version 1.
DT 03-AUG-2022, entry version 152.
DE RecName: Full=Syncytin-B {ECO:0000303|PubMed:15644441};
DE Contains:
DE RecName: Full=Surface protein {ECO:0000303|PubMed:15644441};
DE Short=SU {ECO:0000303|PubMed:15644441};
DE Contains:
DE RecName: Full=Transmembrane protein {ECO:0000303|PubMed:15644441};
DE Short=TM {ECO:0000303|PubMed:15644441};
DE Flags: Precursor;
GN Name=Synb {ECO:0000312|MGI:MGI:3045308};
OS Mus musculus (Mouse).
OC Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Mammalia;
OC Eutheria; Euarchontoglires; Glires; Rodentia; Myomorpha; Muroidea; Muridae;
OC Murinae; Mus; Mus.
OX NCBI_TaxID=10090;
RN [1] {ECO:0000312|EMBL:AAW62450.1}
RP NUCLEOTIDE SEQUENCE [GENOMIC DNA], FUNCTION, TISSUE SPECIFICITY, AND
RP DEVELOPMENTAL STAGE.
RC STRAIN=C57BL/6J {ECO:0000312|EMBL:AAW62450.1};
RX PubMed=15644441; DOI=10.1073/pnas.0406509102;
RA Dupressoir A., Marceau G., Vernochet C., Benit L., Kanellopoulos C.,
RA Sapin V., Heidmann T.;
RT "Syncytin-A and syncytin-B, two fusogenic placenta-specific murine envelope
RT genes of retroviral origin conserved in Muridae.";
RL Proc. Natl. Acad. Sci. U.S.A. 102:725-730(2005).
RN [2] {ECO:0000312|EMBL:BAC39647.1}
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC STRAIN=C57BL/6J; TISSUE=Head;
RX PubMed=16141072; DOI=10.1126/science.1112014;
RA Carninci P., Kasukawa T., Katayama S., Gough J., Frith M.C., Maeda N.,
RA Oyama R., Ravasi T., Lenhard B., Wells C., Kodzius R., Shimokawa K.,
RA Bajic V.B., Brenner S.E., Batalov S., Forrest A.R., Zavolan M., Davis M.J.,
RA Wilming L.G., Aidinis V., Allen J.E., Ambesi-Impiombato A., Apweiler R.,
RA Aturaliya R.N., Bailey T.L., Bansal M., Baxter L., Beisel K.W., Bersano T.,
RA Bono H., Chalk A.M., Chiu K.P., Choudhary V., Christoffels A.,
RA Clutterbuck D.R., Crowe M.L., Dalla E., Dalrymple B.P., de Bono B.,
RA Della Gatta G., di Bernardo D., Down T., Engstrom P., Fagiolini M.,
RA Faulkner G., Fletcher C.F., Fukushima T., Furuno M., Futaki S.,
RA Gariboldi M., Georgii-Hemming P., Gingeras T.R., Gojobori T., Green R.E.,
RA Gustincich S., Harbers M., Hayashi Y., Hensch T.K., Hirokawa N., Hill D.,
RA Huminiecki L., Iacono M., Ikeo K., Iwama A., Ishikawa T., Jakt M.,
RA Kanapin A., Katoh M., Kawasawa Y., Kelso J., Kitamura H., Kitano H.,
RA Kollias G., Krishnan S.P., Kruger A., Kummerfeld S.K., Kurochkin I.V.,
RA Lareau L.F., Lazarevic D., Lipovich L., Liu J., Liuni S., McWilliam S.,
RA Madan Babu M., Madera M., Marchionni L., Matsuda H., Matsuzawa S., Miki H.,
RA Mignone F., Miyake S., Morris K., Mottagui-Tabar S., Mulder N., Nakano N.,
RA Nakauchi H., Ng P., Nilsson R., Nishiguchi S., Nishikawa S., Nori F.,
RA Ohara O., Okazaki Y., Orlando V., Pang K.C., Pavan W.J., Pavesi G.,
RA Pesole G., Petrovsky N., Piazza S., Reed J., Reid J.F., Ring B.Z.,
RA Ringwald M., Rost B., Ruan Y., Salzberg S.L., Sandelin A., Schneider C.,
RA Schoenbach C., Sekiguchi K., Semple C.A., Seno S., Sessa L., Sheng Y.,
RA Shibata Y., Shimada H., Shimada K., Silva D., Sinclair B., Sperling S.,
RA Stupka E., Sugiura K., Sultana R., Takenaka Y., Taki K., Tammoja K.,
RA Tan S.L., Tang S., Taylor M.S., Tegner J., Teichmann S.A., Ueda H.R.,
RA van Nimwegen E., Verardo R., Wei C.L., Yagi K., Yamanishi H.,
RA Zabarovsky E., Zhu S., Zimmer A., Hide W., Bult C., Grimmond S.M.,
RA Teasdale R.D., Liu E.T., Brusic V., Quackenbush J., Wahlestedt C.,
RA Mattick J.S., Hume D.A., Kai C., Sasaki D., Tomaru Y., Fukuda S.,
RA Kanamori-Katayama M., Suzuki M., Aoki J., Arakawa T., Iida J., Imamura K.,
RA Itoh M., Kato T., Kawaji H., Kawagashira N., Kawashima T., Kojima M.,
RA Kondo S., Konno H., Nakano K., Ninomiya N., Nishio T., Okada M., Plessy C.,
RA Shibata K., Shiraki T., Suzuki S., Tagami M., Waki K., Watahiki A.,
RA Okamura-Oho Y., Suzuki H., Kawai J., Hayashizaki Y.;
RT "The transcriptional landscape of the mammalian genome.";
RL Science 309:1559-1563(2005).
RN [3] {ECO:0000312|Proteomes:UP000000589}
RP NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC STRAIN=C57BL/6J;
RX PubMed=19468303; DOI=10.1371/journal.pbio.1000112;
RA Church D.M., Goodstadt L., Hillier L.W., Zody M.C., Goldstein S., She X.,
RA Bult C.J., Agarwala R., Cherry J.L., DiCuccio M., Hlavina W., Kapustin Y.,
RA Meric P., Maglott D., Birtle Z., Marques A.C., Graves T., Zhou S.,
RA Teague B., Potamousis K., Churas C., Place M., Herschleb J., Runnheim R.,
RA Forrest D., Amos-Landgraf J., Schwartz D.C., Cheng Z., Lindblad-Toh K.,
RA Eichler E.E., Ponting C.P.;
RT "Lineage-specific biology revealed by a finished genome assembly of the
RT mouse.";
RL PLoS Biol. 7:E1000112-E1000112(2009).
RN [4] {ECO:0000312|EMBL:AAI37939.1}
RP NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RC TISSUE=Brain;
RX PubMed=15489334; DOI=10.1101/gr.2596504;
RG The MGC Project Team;
RT "The status, quality, and expansion of the NIH full-length cDNA project:
RT the Mammalian Gene Collection (MGC).";
RL Genome Res. 14:2121-2127(2004).
RN [5] {ECO:0000305}
RP FUNCTION, AND MUTAGENESIS OF LYS-495.
RX PubMed=18077339; DOI=10.1073/pnas.0707873105;
RA Mangeney M., Renard M., Schlecht-Louf G., Bouallaga I., Heidmann O.,
RA Letzelter C., Richaud A., Ducos B., Heidmann T.;
RT "Placental syncytins: Genetic disjunction between the fusogenic and
RT immunosuppressive activity of retroviral envelope proteins.";
RL Proc. Natl. Acad. Sci. U.S.A. 104:20534-20539(2007).
RN [6] {ECO:0000305}
RP TISSUE SPECIFICITY, AND DEVELOPMENTAL STAGE.
RX PubMed=18448564; DOI=10.1242/dev.020099;
RA Simmons D.G., Natale D.R., Begay V., Hughes M., Leutz A., Cross J.C.;
RT "Early patterning of the chorion leads to the trilaminar trophoblast cell
RT structure in the placental labyrinth.";
RL Development 135:2083-2091(2008).
RN [7] {ECO:0000305}
RP FUNCTION, AND DISRUPTION PHENOTYPE.
RX PubMed=22032925; DOI=10.1073/pnas.1112304108;
RA Dupressoir A., Vernochet C., Harper F., Guegan J., Dessen P., Pierron G.,
RA Heidmann T.;
RT "A pair of co-opted retroviral envelope syncytin genes is required for
RT formation of the two-layered murine placental syncytiotrophoblast.";
RL Proc. Natl. Acad. Sci. U.S.A. 108:E1164-E1173(2011).
RN [8] {ECO:0000305}
RP FUNCTION, AND INDUCTION.
RX PubMed=27589388; DOI=10.1371/journal.pgen.1006289;
RA Redelsperger F., Raddi N., Bacquin A., Vernochet C., Mariot V., Gache V.,
RA Blanchard-Gutton N., Charrin S., Tiret L., Dumonceaux J., Dupressoir A.,
RA Heidmann T.;
RT "Genetic evidence that captured retroviral envelope syncytins contribute to
RT myoblast fusion and muscle sexual dimorphism in mice.";
RL PLoS Genet. 12:E1006289-E1006289(2016).
CC -!- FUNCTION: This endogenous retroviral envelope protein has retained its
CC original fusogenic properties (PubMed:15644441, PubMed:18077339,
CC PubMed:22032925, PubMed:27589388). Together with Syna, participates in
CC trophoblast fusion and the formation of a syncytium during placenta
CC morphogenesis (PubMed:22032925). Synb is specifically involved in
CC formation of syncytiotrophoblast layer II (SynT-II) (PubMed:22032925).
CC Promotes myoblast fusion, and may play a role in regeneration of
CC damaged muscle tissue in males (PubMed:27589388). May have
CC immunosuppressive activity (PubMed:18077339).
CC {ECO:0000269|PubMed:15644441, ECO:0000269|PubMed:18077339,
CC ECO:0000269|PubMed:22032925}.
CC -!- SUBUNIT: The mature protein consists of a trimer of SU-TM heterodimers
CC (Probable). The SU-TM heterodimers are attached by a labile interchain
CC disulfide bond (By similarity). {ECO:0000250|UniProtKB:Q9UQF0,
CC ECO:0000305}.
CC -!- SUBCELLULAR LOCATION: [Surface protein]: Cell membrane {ECO:0000305};
CC Peripheral membrane protein {ECO:0000305}. Note=The surface protein is
CC not anchored to the membrane, but localizes to the extracellular
CC surface through its binding to TM. {ECO:0000250|UniProtKB:Q9UQF0}.
CC -!- SUBCELLULAR LOCATION: [Transmembrane protein]: Cell membrane
CC {ECO:0000305}; Single-pass membrane protein {ECO:0000255}.
CC -!- TISSUE SPECIFICITY: Highly expressed in placenta where it localizes to
CC syncytiotrophoblasts of the labyrinthine zona (PubMed:15644441).
CC Specifically localizes to syncytiotrophoblast layer II (SynT-II)
CC (PubMed:18448564). Also detected at very low levels in ovary
CC (PubMed:15644441). {ECO:0000269|PubMed:15644441,
CC ECO:0000269|PubMed:18448564}.
CC -!- DEVELOPMENTAL STAGE: Expressed in the placental labyrinth from stage
CC 8.5 dpc onwards. {ECO:0000269|PubMed:18448564}.
CC -!- INDUCTION: In males, up-regulated in regenerating muscle tissue after
CC injury. {ECO:0000269|PubMed:27589388}.
CC -!- PTM: Synthesized as an inactive precursor that is heavily N-
CC glycosylated and processed likely by furin in the Golgi to yield the
CC mature SU and TM proteins. The cleavage site between SU and TM requires
CC the minimal sequence [KR]-X-[KR]-R. {ECO:0000250|UniProtKB:Q9UQF0}.
CC -!- PTM: The CXXC motif is highly conserved across a broad range of
CC retroviral envelope proteins. It is thought to participate in the
CC formation of a labile disulfide bond possibly with the CX6CC motif
CC present in the transmembrane protein. Isomerization of the intersubunit
CC disulfide bond to an SU intrachain disulfide bond is thought to occur
CC upon receptor recognition in order to allow membrane fusion.
CC {ECO:0000250|UniProtKB:Q9UQF0}.
CC -!- DISRUPTION PHENOTYPE: Viable, although growth is retarded and neonate
CC numbers are reduced (PubMed:22032925). In the placental labyrinth,
CC formation of syncytiotrophoblast layer II (SynT-II) is abnormal with
CC reduced cell fusion and progressive expansion of maternal blood
CC lacunae(PubMed:22032925). Unfused SynT-II cells form dense plaque-like
CC structures between adjacent cells, which resemble cell junctions and
CC are associated with high expression levels of GJB6/connexin-30
CC (PubMed:22032925). Formation of syncytiotrophoblast layer I (SynT-I) is
CC grossly normal (PubMed:22032925). Adult male mice have a 15% reduction
CC in muscle mass compared to wild type, probably due to defects in
CC myoblast fusion (PubMed:27589388). Double knockouts of Syna and Synb
CC are embryonic lethal at stage 9.5 dpc to 10.5 dpc, indicating a more
CC severe phenotype than the Syna single knockout (PubMed:22032925).
CC {ECO:0000269|PubMed:22032925, ECO:0000269|PubMed:27589388}.
CC -!- MISCELLANEOUS: The mouse genome contains a high percentage of proviral-
CC like elements, also called endogenous retroviruses (ERVs) that are the
CC genomic traces of ancient infections of the germline by exogenous
CC retroviruses. Although most of these elements are defective, some have
CC conserved a functional envelope (env) gene, most probably diverted by
CC the host for its benefit. {ECO:0000305}.
CC -!- SIMILARITY: Belongs to the gamma type-C retroviral envelope protein
CC family. {ECO:0000305}.
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DR EMBL; AY849977; AAW62450.1; -; Genomic_DNA.
DR EMBL; AK086309; BAC39647.1; -; mRNA.
DR EMBL; AC134575; -; NOT_ANNOTATED_CDS; Genomic_DNA.
DR EMBL; BC137938; AAI37939.1; -; mRNA.
DR EMBL; BC137956; AAI37957.1; -; mRNA.
DR RefSeq; NP_775596.1; NM_173420.3.
DR RefSeq; XP_006519055.1; XM_006518992.3.
DR RefSeq; XP_006519057.1; XM_006518994.3.
DR RefSeq; XP_006519058.1; XM_006518995.3.
DR RefSeq; XP_006519059.1; XM_006518996.2.
DR AlphaFoldDB; Q8BI41; -.
DR SMR; Q8BI41; -.
DR STRING; 10090.ENSMUSP00000061107; -.
DR GlyGen; Q8BI41; 4 sites.
DR iPTMnet; Q8BI41; -.
DR PhosphoSitePlus; Q8BI41; -.
DR PaxDb; Q8BI41; -.
DR PRIDE; Q8BI41; -.
DR DNASU; 239167; -.
DR Ensembl; ENSMUST00000059362; ENSMUSP00000061107; ENSMUSG00000047977.
DR Ensembl; ENSMUST00000184652; ENSMUSP00000139267; ENSMUSG00000098773.
DR GeneID; 239167; -.
DR KEGG; mmu:239167; -.
DR UCSC; uc007umg.1; mouse.
DR CTD; 239167; -.
DR MGI; MGI:3045308; Synb.
DR VEuPathDB; HostDB:ENSMUSG00000047977; -.
DR VEuPathDB; HostDB:ENSMUSG00000098773; -.
DR eggNOG; ENOG502SD08; Eukaryota.
DR GeneTree; ENSGT00940000163436; -.
DR HOGENOM; CLU_506176_0_0_1; -.
DR InParanoid; Q8BI41; -.
DR OMA; SQTPCIQ; -.
DR OrthoDB; 451884at2759; -.
DR PhylomeDB; Q8BI41; -.
DR TreeFam; TF332233; -.
DR BioGRID-ORCS; 239167; 0 hits in 40 CRISPR screens.
DR PRO; PR:Q8BI41; -.
DR Proteomes; UP000000589; Chromosome 14.
DR RNAct; Q8BI41; protein.
DR Bgee; ENSMUSG00000047977; Expressed in trophectoderm and 4 other tissues.
DR GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR GO; GO:0005886; C:plasma membrane; IEA:UniProtKB-SubCell.
DR GO; GO:0060716; P:labyrinthine layer blood vessel development; IMP:MGI.
DR GO; GO:0007520; P:myoblast fusion; IMP:MGI.
DR GO; GO:0014905; P:myoblast fusion involved in skeletal muscle regeneration; IMP:MGI.
DR GO; GO:0007519; P:skeletal muscle tissue development; IMP:MGI.
DR GO; GO:0000768; P:syncytium formation by plasma membrane fusion; IDA:MGI.
DR InterPro; IPR018154; TLV/ENV_coat_polyprotein.
DR PANTHER; PTHR10424; PTHR10424; 1.
DR Pfam; PF00429; TLV_coat; 1.
PE 1: Evidence at protein level;
KW Cell membrane; Developmental protein; Disulfide bond; ERV; Glycoprotein;
KW Membrane; Reference proteome; Signal; Transmembrane; Transmembrane helix.
FT SIGNAL 1..17
FT /evidence="ECO:0000255"
FT CHAIN 18..618
FT /note="Syncytin-B"
FT /id="PRO_5009346813"
FT CHAIN 18..418
FT /note="Surface protein"
FT /evidence="ECO:0000305"
FT /id="PRO_0000440575"
FT CHAIN 419..618
FT /note="Transmembrane protein"
FT /evidence="ECO:0000305"
FT /id="PRO_0000440576"
FT TOPO_DOM 18..545
FT /note="Extracellular"
FT /evidence="ECO:0000305"
FT TRANSMEM 546..566
FT /note="Helical"
FT /evidence="ECO:0000255"
FT TOPO_DOM 567..618
FT /note="Cytoplasmic"
FT /evidence="ECO:0000305"
FT REGION 422..442
FT /note="Fusion peptide"
FT /evidence="ECO:0000305"
FT REGION 482..498
FT /note="Immunosuppression"
FT /evidence="ECO:0000305|PubMed:18077339"
FT MOTIF 44..47
FT /note="CXXC"
FT /evidence="ECO:0000305"
FT MOTIF 499..507
FT /note="CX6CC"
FT /evidence="ECO:0000305"
FT SITE 418..419
FT /note="Cleavage"
FT /evidence="ECO:0000250|UniProtKB:Q9UQF0"
FT CARBOHYD 27
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 184
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 274
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT CARBOHYD 357
FT /note="N-linked (GlcNAc...) asparagine"
FT /evidence="ECO:0000255"
FT DISULFID 44..507
FT /note="Interchain (between SU and TM chains, or C-47 with
FT C-507); in linked form"
FT /evidence="ECO:0000250|UniProtKB:Q9UQF0"
FT DISULFID 44..47
FT /evidence="ECO:0000250|UniProtKB:P23064"
FT DISULFID 499..506
FT /evidence="ECO:0000250|UniProtKB:P60508"
FT MUTAGEN 495
FT /note="K->R: Loss of immunosuppressive activity. No effect
FT on fusogenic activity."
FT /evidence="ECO:0000269|PubMed:18077339"
SQ SEQUENCE 618 AA; 69514 MW; 1D4B54588727FC31 CRC64;
MTGFWVLCFV LFPSSLSYPE SWMPLVNLTH HILRDTNSSL FSNCWVCLST QTQRSLAVPA
PLSIWTDTPM KLHLTYSVRP FSGSFSISDI ERRLRLFRPL TASYSFHNPD RRAIAFLQLV
SSTGIFRIIT RITSVIYPHK DRFFESAQRP LWGPLFTETV LRSQAPLCIS RFFKVSAYAT
FVGNLSASLC NYTMHISPST SHENLDLSTT HTFKQAMKRP DAKWKNPLRF SGPPSLIFSK
PAYYPCPTDI KHCHTSPATP WMHCPQAPFG TCYNLTLFEP DNSTHPVTMS VNPTHFKVKL
QGHRDPYPLS HYQPLTGAAL SGQYSVWENE ITVQENWDIT SNIFSHLLSF SYAFCLNSSG
VFFLCGTSTY ICLPANWSGV CTLVFQYPDI ELLPNNQTVP VPLFASVLSS DSVLRPKRSP
HLFPFLAGLG ISSALGTGIA GLATSTLYFQ QLSKVLSETL EEIAASITTL QNQIDSLAGV
VLQNRRALDL ITAEKGGTCL FLQEECCFYV NQSGIVRDAA RKLQERASEL GQHSDSWGQW
PDLGRWLPWL TPFLGPLLFL FFLLTFGSCL LNCLTRFVSQ RLGSFVQDTA KRHVDSILQN
FQYKKLPQDS PDEDTIPT
