Transcription factors of the Sox family arose around the advent of multicellularity in animals, arguing that their ability to regulate the expression of extracellular matrix, cell adhesion and signaling molecules may have been instrumental in the generation of metazoans. In particular, during vertebrate evolution, the Sox family experienced a phase of expansion that led to the appearance of groups of highly homologous Sox proteins and the division of existing Sox protein functions among group members. It furthermore allowed Sox transcription factors to acquire numerous novel functions. These past events of subfunctionalization and neofunctionalization can still be recognized today in all groups of the Sox family. They have led to partial functional redundancies, but also to interesting species-specific variations in the developmental roles of Sox proteins as shown here for the SoxB and the SoxE groups.

Authors and Affiliations

1. Institut für Biochemie, Emil-Fischer-Zentrum, Universität Erlangen-Nürnberg, Fahrstr. 17, 91054, Erlangen, Germany

   S. I. E. Guth & M. Wegner

Corresponding author

Correspondence toM. Wegner.

Received 18 March 2008; received after revision 21 April 2008; accepted 29 April 2008

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