drb nih talk jan 2009

TBX5: Clues about Heart-Limb Development

• Holt-Oram Syndrome• Mapping and Cloning TBX5• TBX5 Mutations and Cell Biology • T Box Genes• Organ and Limb Development

NIDCR/NIH January 15, 2009

David R. Bachinsky, Ph.D.

TBX5 mutant mouse on bottom. Photo: Malcolm Logan

TBX dimers bound to DNA.. Muller and Herrmann, Nature (1997) 389:884

Moody, Principles of Developmental Genetics, AP Press, 2007.

(Upper) Three-dimensional structure of the X. laevis Xbra T-box bound to a 24-nt DNA duplex indicating the location of residues Gly-80 (red) and Arg-237 (yellow) mutated in the missense

mutations Gly80Arg, Arg237Gln, and Arg237Trp

Basson C. T. et.al. PNAS 1999;96:2919-2924

©1999 by The National Academy of Sciences

Fan, C. et al. J. Biol. Chem. 2003;278:8780-8785

Immunostaining of NIH-3T3 cells expressing human TBX5

Kulisz and Simon, Mol Cell Bio (2008) 28:1553

Camarata etal. J Cell Bio (2006) 174:339

T Box History

• 1927-Brachyury or T gene identified, lethal in homozygotes and a short tail in heterozygotes.

• 1995-first mammalian gene positionally cloned

• DNA binding domain-T box domain identified

• 18 members of gene family, 5 subfamilies

Horton etal. Dev Genes Evol (2008) 218:613

Published by AAAS

E. N. Olson Science 313, 1922 -1927 (2006)

Fig. 3. The heart of Drosophila

Published by AAAS

E. N. Olson Science 313, 1922 -1927 (2006)

Fig. 4. Schematic of transcriptional networks involved in mammalian heart development

Plageman, T. F. et al. J. Biol. Chem. 2004;279:19026-19034

The T-box binding consensus sequences of the ANF promoter are required for regulation by Tbx5 and Tbx20

Moskowitz etal. Cell (2007) 129:1365

Chick embryos 4 Day Gestation, in situ hybridization. The cells expressing Tbx5 will form a wing; those expressing Tbx4 will form a leg. Tbx4 and Tbx5 code for related gene regulatory proteins, which are thought to dictate which type of limb develops. H. Ohuchi et al., Development (1998)125:51–60

Logan, M. Development 2003;130:6401-6410

(A) Representation of the prospective limb territories in a stage 15 chick embryo

Logan, M. Development 2003;130:6401-6410

Representation of the signals required for forelimb initiation and subsequent limb outgrowth in the mouse

Rodriguez-Esteban etal, Nature (1999) 398:814

TBX Genes (Products) and Associated Human

Diseases• T gene Spinal Bifida• TBX1 DiGeorge Syndrome (CATCH 22)• TBX3 Ulnar Mammary Syndrome (UMS)• TBX4 Small patella• TBX5 Holt-Oram Syndrome (HOS, Heart-Hand)• TBX19 POMC Deficiency (TPIT)• TBX20 Heart Defects (septal, conduction defects)• TBX15 Acromegaloid facial appearance (candidate)• TBX21 Asthma (TBET)• TBX22 Cleft palate with ankyloglossia (X linked)

Collaborators

• Jonathan and Christine (Kricket) Seidman• Craig Basson• Robert Lin• Johann Soults• Tatiana Levi• Raju Kucherlapati• Cynthia Morton

Horton etal., Dev Genes Evol (2008) 218:613.

Published by AAAS

E. N. Olson Science 313, 1922 -1927 (2006)

Fig. 2. Simplified structures of different types of hearts, showing schematic diagrams of hearts and directions of blood flow

Hasson, P. et al. Development 2007;134:85-92

Model depicting two phases of limb development

Published by AAAS

E. N. Olson Science 313, 1922 -1927 (2006)

Fig. 2. Simplified structures of different types of hearts, showing schematic diagrams of hearts and directions of blood flow

GRN subcircuits used in both Drosophila and sea urchin development

Davidson E. H., Levine M. S. PNAS 2008;105:20063-20066

©2008 by National Academy of Sciences

Bruneau, Nature (2008) 451:943

drb nih talk jan 2009

Technology

cloning tbx5 tbx5 mutations

limb development nidcrnih

human tbx5

tbx5 code

phases of limb development

mammalian heart development

cell biology t box genes

tbx5 mutant mouse