Brain-expressed X-linked protein 1 homolog; Reduced expression protein 3;REX-3
Organism
Mus musculus (Mouse)
NCBI Taxonomy ID
10090
Chromosome Location
chr:X;132748511-132750052;-1
View in Ensembl genome browser
Function in Stage
Uncertain
Function in Cell Type
Uncertain
Probability (GAS) of Function in Spermatogenesis
0.140462337 The probability was calculated by GAS algorithm, ranging from 0 to 1. The closer it is to 1, the more possibly it functions in spermatogenesis.
Description
Temporarily unavailable
Abstract of related literatures
1. Parthenogenetic and normal blastocysts were compared using differential display analysis as a means to identify new imprinted genes. A single gene was identified with increased expression in parthenogenetic blastocysts, suggesting it might be an imprinted gene expressed from the maternally inherited allele. The gene, named Bex1 (brainexpressedX-linked gene), maps near Plp on the mouse X chromosome and to Xq22 in humans. Database homology searches revealed two additional uncharacterized cDNAs similar to Bex1 that were named Bex2 and Bex3. Allele-specific expression analysis of Bex1 using F1 blastocysts indicated an excess of transcript expressed from the maternally inherited allele compared with the paternally inherited allele. This excess level of transcript derived from the maternally inherited allele may be due to imprinted X inactivation of the paternally inherited allele in the extraembryonic lineages of female embryos rather than a result of genomic imprinting. PMID: [10072429]
2. In the presence of retinoic acid (RA), F9 murine teratocarcinoma cells differentiate into cells resembling the extra-embryonic endoderm of the early mouse embryo. Using differential hybridization, we have cloned and characterized six cDNAs corresponding to mRNAs that exhibit reduced expression in F9 cells following RA treatment. Two of these cDNAs encode novel genes (REX-2 and REX-3). The other isolated cDNAs encode genes that have been previously described in other contexts: 1-4 (cyclin D3); 2-10 (pyruvate kinase); 2-12 (glutathione S-transferase); and 2-17 (GLUT 3). The mRNA levels of these genes are reduced by RA or RA plus theophylline and cAMP (RACT) only after 48 h of treatment, and continue to decrease at 96 h. The half-lives of these mRNAs are not changed by RA treatment, indicating that these mRNAs may be regulated through a transcriptional mechanism. In isoleucine-deprived cells, which are growth arrested but do not differentiate, the steady state mRNA levels of genes Rex 2, Rex 3, pyruvate kinase and GLUT 3 are not reduced, in contrast to cyclin D3 and glutathione S-transferase. The expression of the REX-2, REX-3, pyruvate kinase, glutathione S-transferase and GLUT 3 genes is reduced by RACT to the same extent in F9 RARgamma-/- and RARalpha-/- lines as in F9-Wt. In contrast, cyclin D3 exhibits lower mRNA expression in F9 RARgamma-/- and RARalpha-/- stem cells, and this mRNA is not decreased by RACT treatment. Overexpression of cyclin D3 blocks the RA-induced growth arrest of F9 cells, indicating that the downregulation of this gene following RA treatment may constitute a necessary step in the cascade of events leading to growth inhibition by RA. PMID: [9806360]
3. The mouse (Mus musculus) is the premier animal model for understanding human disease and development. Here we show that a comprehensive understanding of mouse biology is only possible with the availability of a finished, high-quality genome assembly. The finished clone-based assembly of the mouse strain C57BL/6J reported here has over 175,000 fewer gaps and over 139 Mb more of novel sequence, compared with the earlier MGSCv3 draft genome assembly. In a comprehensive analysis of this revised genome sequence, we are now able to define 20,210 protein-coding genes, over a thousand more than predicted in the human genome (19,042 genes). In addition, we identified 439 long, non-protein-coding RNAs with evidence for transcribed orthologs in human. We analyzed the complex and repetitive landscape of 267 Mb of sequence that was missing or misassembled in the previously published assembly, and we provide insights into the reasons for its resistance to sequencing and assembly by whole-genome shotgun approaches. Duplicated regions within newly assembled sequence tend to be of more recent ancestry than duplicates in the published draft, correcting our initial understanding of recent evolution on the mouse lineage. These duplicates appear to be largely composed of sequence regions containing transposable elements and duplicated protein-coding genes; of these, some may be fixed in the mouse population, but at least 40% of segmentally duplicated sequences are copy number variable even among laboratory mouse strains. Mouse lineage-specific regions contain 3,767 genes drawn mainly from rapidly-changing gene families associated with reproductive functions. The finished mouse genome assembly, therefore, greatly improves our understanding of rodent-specific biology and allows the delineation of ancestral biological functions that are shared with human from derived functions that are not. PMID: [19468303]
4. The National Institutes of Health's Mammalian Gene Collection (MGC) project was designed to generate and sequence a publicly accessible cDNA resource containing a complete open reading frame (ORF) for every human and mouse gene. The project initially used a random strategy to select clones from a large number of cDNA libraries from diverse tissues. Candidate clones were chosen based on 5'-EST sequences, and then fully sequenced to high accuracy and analyzed by algorithms developed for this project. Currently, more than 11,000 human and 10,000 mouse genes are represented in MGC by at least one clone with a full ORF. The random selection approach is now reaching a saturation point, and a transition to protocols targeted at the missing transcripts is now required to complete the mouse and human collections. Comparison of the sequence of the MGC clones to reference genome sequences reveals that most cDNA clones are of very high sequence quality, although it is likely that some cDNAs may carry missense variants as a consequence of experimental artifact, such as PCR, cloning, or reverse transcriptase errors. Recently, a rat cDNA component was added to the project, and ongoing frog (Xenopus) and zebrafish (Danio) cDNA projects were expanded to take advantage of the high-throughput MGC pipeline. PMID: [15489334]
5. Through screening a human fetal brain cDNA library, a cDNA similar to the mouse Bex1 was isolated. This new gene was named brain expressed X-linked protein 1 (BEX1). Northern blot analysis revealed a 1.0 kb transcript highly expressed in brain, pancreas, testis, and ovary, with lower levels present in heart, placenta, liver, kidney, spleen, thymus, prostate, small intestine, colon (no mucus), thyroid, spinal cord, and adrenal gland. No hybridization signal was seen in lung, skeletal muscle, peripheral blood leukocyte, stomach, lymph node, trachea, and bone marrow. The BEX1 gene was localized to chromosome band Xq22 between markers between DXS990 and DXS1059 by screening Stanford radiation hybrid G3 panels. In situ hybridization of mouse testis using BEX1 as a probe detected the signal in the pachytene spermatocytes and spermatids but not in spermatogonia. Furthermore, it was not detected at 6, 9, and 12 days postpartum, was present in low amount on Days 15 and 18 and its expression increased sharply after the initiation of puberty (about 21 days) in mouse testis. PMID: [11989783]
6. Olfactory marker protein (OMP) is a ubiquitous, cytoplasmic protein found in mature olfactory receptor neurons of all vertebrates. Electrophysiological and behavioral studies demonstrate that it is a modulator of the olfactory signal transduction pathway. Here, we demonstrate that the solution structure of OMP, as determined by NMR studies, is a single globular domain protein comprised of eight beta-strands forming two beta-sheets oriented orthogonally to one another, thus exhibiting a "beta-clam" or "beta-sandwich" fold: beta-sheet 1 is comprised of beta3-beta8-beta1-beta2 and beta-sheet 2 contains beta6-beta5-beta4-beta7. Insertions include two, long alpha-helices located on opposite sides of the beta-clam and three flexible loops. The juxtaposition of beta-strands beta6-beta5-beta4-beta7-beta2-beta1-beta8-beta3 forms a continuously curved surface and encloses one side of the beta-clam. The "cleft" formed by the two beta-sheets is opposite to the closed end of the beta-clam. Using a peptide titration series, we have identified this cleft as the binding surface for a peptide derived from the Bex1 protein. The highly conserved Omega-loop structure adjacent to the Bex1 peptide-binding surface found in OMP may be the site of additional OMP-protein interactions related to its role in modulating olfactory signal transduction. Thus, the interaction between the OMP and Bex1 proteins could facilitate the interaction between OMP and other components of the olfactory signaling pathway. PMID: [12054873]
7. Olfactory marker protein (OMP) expression is a hallmark of mature vertebrate olfactory receptor neurons (ORNs). Evidence for OMP function derives from altered behavioral and electrophysiological activities of OMP-KO mice. The molecular basis for the altered phenotype following the deletion of OMP is still unclear. Recent structural studies predict the involvement of OMP in protein-protein interaction. Here we report the identification of an OMP partner, Bex2, by phage-display screening of an olfactory mucosal cDNA-library. In situ hybridization demonstrates cellular co-localization of OMP mRNA with mRNAs for Bex1, Bex2, and Bex3 in ORNs of olfactory tissue of the mouse. The OMP/Bex interaction has been confirmed by demonstrating the chemical cross-linking of recombinant rat OMP with a synthetic peptide derived from the Bex amino acid sequence. The subcellular localization of Bex and OMP proteins was evaluated in transfected HEK293 cells. Bex is visualized in the nucleus and cytoplasm. Following co-transfection we observed the unexpected presence of some OMP in the nucleus along with Bex. Together, these data argue convincingly that we have identified Bex as an OMP partner whose further characterization will provide insight to the role of OMP and to the mechanism of the OMP/Bex interaction in ORN differentiation and function. PMID: [12911636]
8. Olfactory marker protein (OMP) participates in the olfactory signal transduction pathway. This is evident from the behavioral and electrophysiological deficits of OMP-null mice, which can be reversed by intranasal infection of olfactory sensory neurons with an OMP-expressing adenovirus. Bex, brain expressed X-linked protein, has been identified as a protein that interacts with OMP. We have now further characterized the interaction of OMP and Bex1/2 by in vitro binding assays and by immuno-coprecipitation experiments. OMP is a 19 kDa protein but these immunoprecipitation studies have revealed the unexpected presence of a 38 kDa band in addition to the expected 19 kDa band. Furthermore, the 38 kDa form was preferentially co-immunoprecipitated with Bex from cell extracts. In-gel tryptic digestion, mass spectrometry, and two-dimensional gel electrophoresis indicate that the 38 kDa protein behaves as a covalently cross-linked OMP-homodimer. The 38 kDa band was also identified in western blots of olfactory epithelium demonstrating its presence in vivo. The stabilities and subcellular localizations of the OMP-monomer and -dimer were studied in transfected cells. These results demonstrated that the OMP-dimer is much less stable than the monomer, and that while the monomer is present both in the nuclear and cytosolic compartments, the dimer is preferentially located in a Triton X-100 insoluble cytoskeletal fraction. These novel observations led us to hypothesize that regulation of the level of the rapidly turning-over OMP-dimer and its interaction with Bex1/2 is critical for OMP function in sensory transduction. PMID: [15198671]
9. Bex proteins are expressed from a family of "brain expressed X-linked genes" that are closely linked on the X-chromosome. Bex1 and 2 have been characterized as interacting partners of the olfactory marker protein (OMP). Here we report the distribution of Bex1 and Bex2 mRNAs in several brain regions and the development and characterization of an antibody to mouse Bex1 protein that cross-reacts with Bex2 (but not Bex3), and its use to determine the cellular distribution of Bex proteins in the murine brain. The specificity of the antiserum was characterized by immunoprecipitation and Western blots of tissue and transfected cell extracts and by immunocytochemical analyses of cells transfected with either Bex1 or Bex2. Antibodies preabsorbed with Bex2 still recognize Bex1, while blocking with Bex1 eliminates all immunoreactivity to both Bex1 and Bex2. Bex immunoreactivity (ir) was primarily localized to neuronal cells within several regions of the brain, including the olfactory epithelium, bulb, peri/paraventricular nuclei, suprachiasmatic nucleus, arcuate nucleus, median eminence, lateral hypothalamic area, thalamus, hippocampus, and cerebellum. RT-PCR and in situ hybridization demonstrated the presence of Bex mRNA in several of these regions. Double-label immunocytochemistry indicates that Bex-ir is colocalized with OMP in mature olfactory receptor neurons (ORNs) and in the OMP-positive subpopulation of neurons in hypothalamus. This is the first anatomical mapping of Bex proteins in the mouse brain and their colocalization with OMP in ORNs and hypothalamus. PMID: [15861462]
Signaling adapter molecule involved in p75NTR/NGFRsignaling. Plays a role in cell cycle progression and neuronaldifferentiation. Inhibits neuronal differentiation in response tonerve growth factor (NGF). May act as a link between the cellcycle and neurotrophic factor signaling, possibly by functioningas an upstream modulator of receptor signaling, coordinatingbiological responses to external signals with internal cellularstates (By similarity).
Nucleus. Cytoplasm. Note=Shuttles betweenthe cytoplasm and the nucleus.
Tissue Specificity
Primarily localized to neuronal cells withinseveral regions of the brain, including the olfactory epithelium,bulb, peri/paraventricular nuclei, suprachiasmatic nucleus,arcuate nucleus, median eminence, lateral hypothalamic area,thalamus, hippocampus and cerebellum (at protein level). Expressedin brain, mid term embryos and to a lesser extent in ovary. Intestis, it is expressed in the pachytene spermatocytes andspermatids but not in spermatogonia.
CHAIN 1 128 Protein BEX1. /FTId=PRO_0000229774. MOD_RES 105 105 Phosphoserine (By similarity). CONFLICT 40 40 T -> I (in Ref. 1; AAC61929 and 3; AAD24429). Back to Top