CELL BIOLOGY OF DEVELOPMENT

Ruth Arkell Laboratory Telephone: +61 (0)2 6125 9158 Facsimile: +61 (0)2 6125 8294 Email: ruth.arkell@anu.edu.au

Research Focus

Research within this programme is focused on the identification and characterisation of genes that are required for mammalian embryonic development. Adult form and function is dependent upon the events of embryogenesis and it is crucial for human health that we gain a better understanding of the genetic control of development. There are now over 3000 documented non-chromosomal, multiple congenital anomaly syndromes. Moreover, in recent years it has been recognised that the study of embryology not only enhances our knowledge of congenital defects but also the understanding of later onset diseases that involve, for example, the inappropriate reactivation of genes that control cell growth and differentiation.

One of the most crucial stages of embryonic development is gastrulation. During this period cell movement and cell-cell communication directs differentiation such that a highly patterned embryo with three recognisable axes (anterior-posterior, dorsal-ventral and left-right) is formed. In the mouse, gastrulation begins just after implantation at around 6.5 days post coitum (dpc) and by 9.5 dpc the embryo contains the rudiments of almost every adult structure. In order to identify genes that function during gastrulation we use genetic screens to recover mutants that have a visible mid-gestation phenotype. We are currently investigating several mutant strains that exhibit defective forebrain development. We have identified the mutated gene in many of these strains and are characterising the morphological and molecular defects to reveal the function of the mutated gene.

One current focus of our research is the Zic genes which are vertebrate homologues of the Drosophila pair rule gene, odd-paired. Odd-paired and each of its homologues contain a zinc finger domain that is able to participate in DNA binding and in protein binding and are considered putative transcription factors. Both mouse and human contain five Zic genes, four of which are associated with human congenital defects. My group studies the three Zic genes that are expressed during gastrulation: Zic2, Zic3 and Zic5. In each case we aim to understand the function of these genes during gastrulation at a cellular and molecular level and to piece together the genetic pathway(s) in which these genes participate.

Research Projects

How does Zic2 cause Holoprosencephaly?
Mutation of both Human and Mouse ZIC2 causes a developmental defect of forebrain development known as Holoprosencephaly (HPE). This occurs when the forebrain fails to divide into the left and right hemispheres during embryogenesis. Human and mouse genetics has shown that Shh signalling from the ventral forebrain is required for tis division. We are investigating the developmental cause of HPE in mouse strains that carry a mutation in Zic2 and examining whether Zic2 interacts with Shh to cause HPE.

What is the molecular mechanism of Zic gene function?
Several studies of Zic gene function show that these transcription factors are not always found in the nucleus. We would like to know how the subcellular localisation of these proteins is regulated and what role subcellular localisation plays in Zic gene function during embryogenesis. We are using a cell culture system to examine the manner in which a variety of point mutations in Zic proteins affect their subcellular localisation and nuclear translocation. In addition we aim to identify the mechanism

Recent publications

Collaborators & Linkages

• Ioannis Ragoussis: The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
• Jonathan Flint: The Wellcome Trust Centre for Human Genetics, Roosevelt Drive, Oxford, OX3 7BN, UK
• Thoma Zwaka: Baylor College of Medicine, Department of Molecular and Cellular Biology, Center for Cell and Gene Therapy, One Baylor Plaza, Room N1030, Houston, TX 77030, USA
• Kathy Millen: Department of Human Genetics, University of Chicago, 920 E. 58th Street, CLSC 319, Chicago, Illinois, 60637, USA
• Pat Nolan: Mammalian Genetics Unit, MRC Harwell, Oxfordshire, OX11 0RD, UK
• Dominic Norris: Mammalian Genetics Unit, MRC Harwell, Oxfordshire, OX11 0RD, UK
• Kate Barald: Department of Cell and Developmental Biology , University of Michigan Medical School, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
• Steve Brown: University of Vermont, 89 Beaumont Dr, Burlington, VT 05401, USA
  

Publications (since 2000)

Garrick, D., Sharpe, J., Arkell, R.M., Dobbie, L., Smith, A., Wood, B., Higgs, D., and Gibbons, R. Targeted disruption of the SNF2-like protein Atrx causes trophoblast failure and embryonic lethality. (2006) PLoS Genet. 2(4): e58.

Bogani, D., Willoughby, C., Davies, J., Kaur, K., Mirza, G., Paudyal, A., Haines, H., McKeone, R., Cadman, M., Pieles, G., Schneider, J.E., Bhattacharya, S., Hardy, A., Nolan, P.M., Tripodis, N., Depew, M.J., Chandrasekara, R., Duncan, G., Sharpe, P.T., Greenfield, A., Denny, P., Brown, S.D.M., Ragoussis, J. and Arkell, R. Dissecting the genetic complexity of human 6p deletion syndromes using a region-specific, phenotype-driven mouse screen. (2005) Proc Natl Acad Sci U S A, 102(35): 12477-12482.

Blewitt, M.E., Vickaryous, N.K., Hemley, S.J., Ashe, A., Bruxner, T.J., Preis, J.I., Arkell, R. and Whitelaw, E. An ENU screen for genes involved in variegation in the mouse. (2005) Proc Natl Acad Sci U S A. 102(21):7629-34.

Brown, L., Paraso, M., Arkell, R. and Brown, S. In vitro analysis of partial loss-of-function ZIC2 mutations in holoprosencephaly: alanine tract expansion modulates DNA binding and transactivation. (2005) Hum. Mol. Genet.14(3):411-20.

Bogani, D., Warr, N., Elms, P., Davies, J., Tymowska-Lalanne, Z., Goldsworthy, M., Cox, R.D., Keays, D.A., Flint, J., Wilson, V., Nolan, P. and Arkell, R. New semidominant mutations that affect mouse development. (2004) Genesis 40(2):109-117.

Mallon, A-M., Wilming, L., Weekes, J., Gilbert, J.G.R., Ashurst, J., Peyrefitte, L., Matthews, L., Cadman, M., McKeone, R., Sellick, C., Arkell, R., Botcherby, M.R.M., Strivens, M.A., Campbell, R.D., Gregory, S., Denny, P., Hancock, J.M., Rogers, J. and Brown, S.D.M. Organization and evolution of a gene-rich region of the mouse genome: a 12.7 Mb region deleted in the Del(13)Svea36H mouse. (2004) Genome Research 14(10):1888-1901.

Elms, P., Scurry, A., Davies, J., Willoughby, C., Hacker, T., Bogani, D. and Arkell, R. Overlapping and distinct expression domains of Zic2 and Zic3 during mouse gastrulation. (2004) Gene Expr. Patterns 4(5):505-511.

Elms, P., Siggers, P., Napper, D., Greenfield, A. and Arkell, R. Zic2 is required for neural crest formation and hindbrain patterning during mouse development. (2003) Dev. Biol. 264:391-406.

Curtin, J.A., Quint, E., Tsipouri, V., Arkell, R.M., Cattanach, B., Copp, A.J., Henderson, D.J., Spurr, N., Stanier, P., Fisher, E.M., Nolan, P.M., Steel, K.P., Brown, S.D., Gray, I.C. and Murdoch, J.N. Mutation of Celsr1 disrupts planar polarity of inner ear hair cells and causes severe neural tube defects in the mouse. (2003) Curr. Biol. 13(13):1129-1133.

Murdoch, J.N., Henderson, D.J., Doudney, K., Gaston-Massuet, C., Phillips, H.M., Paternotte, C., Arkell, R., Stanier, P. and Copp, AJ. Disruption of scribble (Scrb1) causes severe neural tube defects in the circletail mouse. (2003) Hum. Mol. Genet. 12(2):87-98.

Arkell, R.M., Cadman, M., Marsland, T., Southwell, A., Thaung, C., Davies, J.R., Clay, T., Beechey, C., Evans, E.P., Strivens, M.A., Brown, S.D.M. and Denny, P. Genetic, physical and phenotypic characterisation of the Del(13)Svea36H mouse mutant. (2001) Mammalian Genome 12:687-694.

Grimmond, S., Larder, R., Van Hateren, N., Siggers, P., Morse, S., Thacker, T., Arkell, R. and Greenfield, A. Expression of a novel mammalian EGF-related gene during mouse neural development. (2001) Mech. Dev. 102(1-2):209-211.

Episkopou, V., Swan, D., Timmons, P., Walsh, J., Andrew, R. and Arkell, R. Induction of the mammalian node requires Arkadia function in the extraembryonic lineages. (2001) Nature 410:825-30.

Grimmond, S., Larder, R., Van Hateren, N., Siggers, P., Hulsebos, T.J., Arkell, R. and Greenfield, A. Cloning, mapping, and expression analysis of a gene encoding a novel mammalian EGF-related protein (SCUBE1). (2000) Genomics 70(1):74-81.

Grimmond, S., Van Hateren, N., Siggers, P., Arkell, R., Larder, R., Soares, MB., de Fatima Bonaldo, M., Smith, L., Tymowska-Lalanne, Z., Wells, C. and Greenfield, A. Sexually dimorphic expression of protease nexin-1 and Vanin-1 in the developing mouse gonad prior to overt differentiation suggests a role in mammalian sexual development. (2000) Hum. Mol. Genet. 9(10):1553-1560.

Nolan, P.M., Peters, J., Strivens, M., Rogers, D., Hagan, J., Spurr, N., Gray, I.C., Vizor, L., Brooker, D., Whitehill, E., Washbourne, R., Hough, T., Greenaway, S., Hewitt, M., Liu, X., McCormack, S., Pickford, K., Selley, R., Wells, C., Tymowska-Lalanne, Z., Roby, P., Glenister, P., Thornton, C., Thaung, C., Stevenson, J-A., Arkell, R., Mburu, P., Hardisty, R., Kiernan, A., Erven, A., Steel, K.P., Voegeling, S., Guenet, J-L., Nickols, C., Sadri, R., Naase, M., Isaacs, A., Davies, K., Browne, M., Fisher, E.M.C., Martin, J., Rastan, S., Brown, S.D.M. and Hunter, J. A systematic genome-wide phenotype-driven mutagenesis programme for gene function studies in the mouse (2000) Nature Genetics 25(4):440-443.