Koen Braat

Biographical Sketch

Koen Braat (1967) studied biology at the Utrecht University with specializations in molecular biology and medical microbiology. In 1999 he obtained his PhD at the Utrecht Universty. He worked in the research group for Comparative Endocrinology and the Hubrecht Laboratory to characterize the stem cells of the gametes (primordial germ cells) in zebrafish .

In November 2000, he joined the group of Prof. Paul Macdonald at the division of Molecular Cell and Developmental Biology  at the University at of Texas in Austin. He investigated regulation of the translation of oskar, a maternal mRNA, which plays a key role in posterior body patterning and germ cell formation in Drosophila melanogaster and revealed an unknown regulatory mechanism by which Oskar protein is restricted to the posterior pole of the oocyte.

In April 2003 he joined the group of Prof. Maarten van Lohuizen at the Netherlands Cancer Institute in the Division of Molecular Genetics. Here he performed a reporter based ERM-tag (enhanced retroviral mutagen) screen to identify new components that regulate the Shh pathway. He also performed in vitro functional genetic screens to identify new oncogenes or tumor suppressor genes involved in tumor formation and in vitro functional genetic screens to identify new genes involved in maintenance of pluripotency of embryonic stem cells.

In Januari 2008 he joined the Regenerative Medicine program in the group of Prof. Paul Coffer at the Wilhelmina’s Childrens Hospital in Utrecht. Here he will focus on the mesenchymal stem cells (MSC), a multipotent stem cell that can differentiate into several lineages (adipogenic, chondrogenic, osteogenic) and investigate the multipotency/differentiation capacities of these stem cells using (genome-wide and gene families) siRNA and shRNA knock-down approaches. He will also investigate the role of PKB signalling in relation to multipotency/differentiation. He is also interested in the epigenetic regulation of potency/differentiation of MSCs. Moreover he wants to understand the immunomodulatory capacities of the MSCs.

Publications

Westerman BA, Braat AK, Taub N, Potman M, Vissers JH, Blom M, Verhoeven E, Stoop H, Gillis A, Velds A, Nijkamp W, Beijersbergen R, Huber LA, Looijenga LH, van Lohuizen M. A genome-wide RNAi screen in mouse embryonic stem cells identifies Mp1 as a key mediator of differentiation. J Exp Med. 2011 Dec 19;208(13):2675-89.

Braat AK, Yan N, Arn E, Harrison D, Macdonald PM. Localization-dependent oskar protein accumulation; control after the initiation of translation. (2004) Dev Cell 7, 125-31.

Braat AK, van de Water S, Korving J, Zivkovic D. A zebrafish vasa morphant abolishes vasa protein but does not affect the establishment of the germline. (2001) Genesis 30, 183-5.

Braat AK, Speksnijder JE, Zivkovic D. Germ line development in fishes. (1999) Int J Dev Biol. 43, 745-60.

Braat AK, Zandbergen T, van de Water S, Goos HJ, Zivkovic D. Characterization of  zebrafish primordial germ cells: morphology and early distribution of vasa RNA.(1999). Dev Dyn. 216, 153-67.

Braat AK, Zandbergen MA, De Vries E, Van Der Burg B, Bogerd J, Goos HJ. Cloning and expression of the zebrafish germ cell nuclear factor. (1999) Mol Reprod Dev. 53, 369-75.

Verheul AF, Kuipers AJ, Braat AK, Dekker HA, Peeters CC, Snippe H, Poolman JT. Development, characterization, and biological properties of meningococcal immunotype L3,7,(8),9-specific monoclonal antibodies. (1994) Clin Diagn Lab Immunol. 1, 729-36.

Verhoef J. Preparation, characterization, and immunogenicity of meningococcal immunotype L2 and L3,7,9 phosphoethanolamine group-containing oligosaccharide-protein conjugates. (1991) Infect Immun. 59, 843-51.