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Formation of the asymmetric pineal complex in zebrafish requires two independently acting transcription factors
Author(s) -
Snelson Corey D.,
Burkart Jarred T.,
Gamse Joshua T.
Publication year - 2008
Publication title -
developmental dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.634
H-Index - 141
eISSN - 1097-0177
pISSN - 1058-8388
DOI - 10.1002/dvdy.21607
Subject(s) - biology , zebrafish , transcription factor , transcription (linguistics) , microbiology and biotechnology , pineal gland , genetics , evolutionary biology , endocrinology , gene , melatonin , linguistics , philosophy
Abstract The pineal complex of zebrafish consists of a pineal organ and a left‐sided parapineal organ. Mutation of the floating head ( flh ) gene, which encodes a homeodomain protein, causes premature termination of pineal cell division without affecting specification or asymmetric placement of the parapineal. The from beyond ( fby ) mutation, a premature stop codon in the T‐domain‐containing protein Tbx2b, disrupts formation of the parapineal while leaving the pineal largely intact. However, flh is reported as being required for tbx2b transcription. To resolve the paradox that flh and tbx2b mutants have opposite phenotypes but have been placed in the same genetic pathway, we have examined transcriptional cross‐regulation in single flh or fby mutants and genetic epistasis in double mutants. Careful analysis shows that flh is not required for tbx2b transcription and double mutants exhibit an additive phenotype. We conclude that Flh and Tbx2b regulate separate programs of pineal and parapineal development. Developmental Dynamics 237:3538–3544, 2008. © 2008 Wiley‐Liss, Inc.