The tinman gene
editThe tinman gene, or tin, is a NK2 homeobox-containing transcription factor in Drosophila flies; with a human homolog - the Nkx2-5 gene.[1] Tin is expressed during the specification of the Cardiac Crescent from the splanchnic mesodermal tissue.[2]
Tinman is dependent upon the JAK-STAT signaling of the precardiac mesoderm to differentiate into a more confined growth pattern for development of visceral mesoderm and the heart.[3] It contributes to the looping of the heart during fetal cardiac development, but has also been found to contribute to the regulation of the heart's electrical system postnatally.[4]
Mutations of the Nkx2-5 gene results in congenital heart defects where holes form within the heart septum of the atria or ventricles. Mutations also result in the Tetralogy of Fallot which results in a "blue skin baby" from lack of properly oxygenated blood.[5] Some holes will close naturally, otherwise surgery is necessary to prevent damage and failure of the heart. Because of its involvement in the conduction system, correctional surgery can lead to abnormalities of heart rates in the patient's adult life, in which case they would require a pacemaker.[6] The Nbx2-5 mutation has also been associated with preeclampsia; though research is still being conducting in this area.[7]
Dr. Kenneth Chien of the University of California at San Diego found a gene knockout model in mice. Only taking tinman from their ventricular cells prior to its utilization in the heart's electrical system, mice developed a collection of problems such as cardiomyopathy, small AV nodes, and heart rate arrhythmias.[8]
References
edit- ^ Bausek, N, Zeidler, MP. Matters of the heart. JAK-STAT. 2012;1(3):208–210. doi:10.4161/jkst.21361
- ^ Golding, M. Fetal Physiology Lecture 20 Cardiovascular System I.
- ^ Bodmer, R. The gene tinman is required for specification of the heart and visceral muscles in Drosophila. The Company of Biologists - Development. 1993;118:719–729. Available at: http://dev.biologists.org/content/118/3/719.long.
- ^ Winslow, R. In 'Tinman' Gene, Scientists See Root Of 2 Heart Defects. The Wall Street Journal. 2004. Available at: http://www.wsj.com/articles/sb109104931954976796
- ^ Winslow, R. In 'Tinman' Gene, Scientists See Root Of 2 Heart Defects. The Wall Street Journal. 2004. Available at: http://www.wsj.com/articles/sb109104931954976796
- ^ Winslow, R. In 'Tinman' Gene, Scientists See Root Of 2 Heart Defects. The Wall Street Journal. 2004. Available at: http://www.wsj.com/articles/sb109104931954976796
- ^ Developing Genetic Therapies for Congenital Heart Defects. MUSC Health - Research . 2013. Available at: http://www.muschealth.org/pn/yir-2013/research/tin-man/index.html
- ^ Winslow, R. In 'Tinman' Gene, Scientists See Root Of 2 Heart Defects. The Wall Street Journal. 2004. Available at: http://www.wsj.com/articles/sb109104931954976796