Brain-specific homeobox explained

Brain-specific homeobox is a protein that in humans is encoded by the BSX gene.^[1]

Structure and expression pattern

Bsx is an evolutionarily highly-conserved homeodomain-containing transcription factor that belongs to the ANTP-class.^[2] In mouse it has been shown to be expressed in the telencephalic septum, pineal gland, the mammillary bodies and arcuate nucleus.^[3]

Function in the hypothalamus

In the hypothalamic arcuate nucleus, Bsx has been demonstrated to be necessary for normal expression levels of the two orexigenic neuropeptides Agouti-related peptide and Neuropeptide Y.^[4]

Function in the pineal gland

In the pineal gland of the clawed frog Xenopus, Bsx is expressed following the circadian rhythm and controls photoreceptor cell differentiation.^[5] In zebrafish Bsx is required for normal development of all cell types within the pineal gland, including melatonin-releasing pinealocytes, photoreceptor cells and leftwards migrating parapineal cells,^[6] which in zebrafish are crucial for the establishment of brain asymmetry.^[7]

Notes and References

1. Web site: Entrez Gene: BSX brain-specific homeobox.
2. Ferrier . David E. K. . Evolution of Homeobox Gene Clusters in Animals: The Giga-Cluster and Primary vs. Secondary Clustering . Frontiers in Ecology and Evolution . 14 April 2016 . 4 . 10.3389/fevo.2016.00036. free . 10023/8685 . free .
3. Cremona . M . Colombo . E . Andreazzoli . M . Cossu . G . Broccoli . V . Bsx, an evolutionary conserved Brain Specific homeoboX gene expressed in the septum, epiphysis, mammillary bodies and arcuate nucleus. . Gene Expression Patterns . January 2004 . 4 . 1 . 47–51 . 14678827. 10.1016/S1567-133X(03)00151-0 .
4. Sakkou . M . Wiedmer . P . Anlag . K . Hamm . A . Seuntjens . E . Ettwiller . L . Tschöp . MH . Treier . M . A role for brain-specific homeobox factor Bsx in the control of hyperphagia and locomotory behavior. . Cell Metabolism . June 2007 . 5 . 6 . 450–63 . 10.1016/j.cmet.2007.05.007 . 17550780. free .
5. D'Autilia . S. . Broccoli . V. . Barsacchi . G. . Andreazzoli . M. . Xenopus Bsx links daily cell cycle rhythms and pineal photoreceptor fate . Proceedings of the National Academy of Sciences . 22 March 2010 . 107 . 14 . 6352–6357 . 10.1073/pnas.1000854107. 20308548 . 2852004 . 2010PNAS..107.6352D . free .
6. Schredelseker . Theresa . Driever . Wolfgang . Bsx controls pineal complex development . Development . 1 July 2018 . 145 . 13 . dev163477 . 10.1242/dev.163477. 29945867 . free .
7. Duboc . Véronique . Dufourcq . Pascale . Blader . Patrick . Roussigné . Myriam . Asymmetry of the Brain: Development and Implications . Annual Review of Genetics . 23 November 2015 . 49 . 1 . 647–672 . 10.1146/annurev-genet-112414-055322. 26442849 .