Alternative titles; symbols
HGNC Approved Gene Symbol: FABP7
Cytogenetic location: 6q22.31 Genomic coordinates (GRCh38): 6:122,749,201-122,784,074 (from NCBI)
Fatty acid-binding proteins (FABPs), such as FABP7, are small cytosolic proteins that enhance intracellular transfer of fatty acids and have a stimulatory effect on enzymes involved in the processes of fatty acid metabolism (Shimizu et al., 1997).
Bennett et al. (1994) used degenerate FABP primers designed from the published sequences of P2 protein, bovine heart, and mouse heart FABP, as well as rat liver and rat heart FABP, to screen a cDNA library from rat brain. They identified a cDNA that contained an open reading frame capable of encoding a protein of 132 amino acids with a predicted molecular weight of 15,000 Da. This protein exhibited 65% sequence identity with rat heart FABP and 70% identity with bovine brain FABP, although it lacked the consensus FABP signature sequence. The B-FABP message was abundant in the brain and the liver, as well as in the MOCH-1 oligodendrocyte cell line. It was abundantly expressed in the brains of 15-day-old embryos, before the appearance of abundant oligodendroglia. Bennett et al. (1994) suggested that B-FABP may play a role in neuronal and glial cell differentiation.
Shimizu et al. (1997) isolated a human FABP cDNA, FABP7, from a fetal brain cDNA library by sequencing of randomly selected clones. The 754-bp cDNA encodes a putative 132-amino acid protein whose sequence is 87 to 91% identical with the FABP sequence from rat and mouse brain and chick retina, and 67% and 59% identical with the sequence of human muscle FABP (FABP3; 134651) and human myelin protein P2 (170715); the identity includes amino acids that affect the ability of the FABPs to bind oleic acids. Northern blot analysis revealed small amounts of a 1.2-kb transcript in adult brain and a shorter transcript in adult skeletal muscle. In contrast, FABP7 was abundantly expressed in fetal brain but was not found in any other tissues. The authors stated that this tissue distribution is different from that seen in mouse and rat brain FABP and chick retina FABP.
Anthony et al. (2005) identified a Cbf1 (147183)-binding site in the promoter of the mouse Blbp gene. They found that this binding site was essential for all Blbp transcription in radial glial cells during central nervous system (CNS) development. Blbp expression was also significantly reduced in the forebrains of mice lacking the Notch1 (190198) and Notch3 (600276) receptors. Anthony et al. (2005) concluded that Blbp is a CNS-specific Notch target gene and suggested that Blbp mediates some aspects of Notch signaling in radial glial cells during development.
By gene expression profiling of glioblastoma multiforme tumors (GBM; see 137800), Liang et al. (2005) found that increased expression of the FABP7 gene, known to be involved in the establishment of the radial glial system in the developing brain, was associated with decreased survival, particularly in younger patients, in 2 unrelated cohorts totaling 105 patients. Transfection of FABP7 into glioma cells in vitro resulted in a 5-fold increase in cell migration compared to control cells, suggesting a functional correlation.
The endocannabinoid anandamide, arachidonoyl ethanolamide (AEA), is a neuromodulatory lipid expected to have limited diffusion through the aqueous cytosol because of its hydrophobic character. In COS-7 cells, Kaczocha et al. (2009) identified FABP5 (605168) and FABP7 as cytosolic proteins that transport AEA from the plasma membrane to subcellular fatty acid amide hydrolase (FAAH; 602935), where it is hydrolyzed and inactivated. FABP3 did not show this specific transport function.
Using suppression subtractive hybridization and quantitative real-time PCR on 12 male Down syndrome (DS; 190685) fetal half-brains and 10 male control fetal half-brains, Sanchez-Font et al. (2003) found that DS brains showed 1.63-fold upregulation of FABP7. Real-time PCR also revealed upregulation of the homeobox transcription factor PKNOX1 (602100) in DS brains. Recombinant PKNOX1 bound weakly to a PBX/POU site in the FABP7 promoter in vitro, but it robustly activated expression of a reporter containing the PBX/POU site when coexpressed with the reporter in human SH-SY5Y neuroblastoma cells, a source of PKNOX1 binding partners, such as PBX1 (176310). Sanchez-Font et al. (2003) postulated that dosage imbalance in trisomy 21 that results in overexpression of PKNOX1 may contribute to or even enhance DS-associated neurologic disorders by causing overexpression of FABP7.
Sanchez-Font et al. (2003) reported that the FABP7 gene maps to chromosome 6q22-q23. During their manual annotation of chromosome 6, Mungall et al. (2003) mapped the FABP7 gene at chromosome 6q22.31.
Anthony, T. E., Mason, H. A., Gridley, T., Fishell, G., Heintz, N. Brain lipid-binding protein is a direct target of Notch signaling in radial glial cells. Genes Dev. 19: 1028-1033, 2005. [PubMed: 15879553] [Full Text: https://doi.org/10.1101/gad.1302105]
Bennett, E., Stenvers, K. L., Lund, P. K., Popko, B. Cloning and characterization of a cDNA encoding a novel fatty acid binding protein from rat brain. J. Neurochem. 63: 1616-1624, 1994. [PubMed: 7931318] [Full Text: https://doi.org/10.1046/j.1471-4159.1994.63051616.x]
Kaczocha, M., Glaser, S. T., Deutsch, D. G. Identification of intracellular carriers for the endocannabinoid anandamide. Proc. Nat. Acad. Sci. 106: 6375-6380, 2009. [PubMed: 19307565] [Full Text: https://doi.org/10.1073/pnas.0901515106]
Liang, Y., Diehn, M., Watson, N., Bollen, A. W., Aldape, K. D., Nicholas, M. K., Lamborn, K. R., Berger, M. S., Botstein, D., Brown, P. O., Israel, M. A. Gene expression profiling reveals molecularly and clinically distinct subtypes of glioblastoma multiforme. Proc. Nat. Acad. Sci. 102: 5814-5819, 2005. [PubMed: 15827123] [Full Text: https://doi.org/10.1073/pnas.0402870102]
Mungall, A. J., Palmer, S. A., Sims, S. K., Edwards, C. A., Ashurst, J. L., Wilming, L., Jones, M. C., Horton, R., Hunt, S. E., Scott, C. E., Gilbert, J. G. R., Clamp, M. E., and 158 others. The DNA sequence and analysis of human chromosome 6. Nature 425: 805-811, 2003. [PubMed: 14574404] [Full Text: https://doi.org/10.1038/nature02055]
Sanchez-Font, M., Bosch-Comas, A., Gonzalez-Duarte, R., Marfany, G. Overexpression of FABP7 in Down syndrome fetal brains is associated with PKNOX1 gene-dosage imbalance. Nucleic Acids Res. 31: 2769-2777, 2003. [PubMed: 12771203] [Full Text: https://doi.org/10.1093/nar/gkg396]
Shimizu, F., Watanabe, T. K., Shinomiya, H., Nakamura, Y., Fujiwara, T. Isolation and expression of a cDNA for human brain fatty acid-binding protein (B-FABP). Biochim. Biophys. Acta 1354: 24-28, 1997. [PubMed: 9375786] [Full Text: https://doi.org/10.1016/s0167-4781(97)00115-2]