Multiple functions of LIM domain-binding CLIM/NLI/Ldb cofactors during zebrafish development.
The crucial involvement of CLIM/NLI/Ldb cofactors for the exertion of the biological activity of LIM homeodomain transcription factors (LIM-HD) has been demonstrated. In this paper we show that CLIM cofactors are widely expressed during zebrafish development with high protein levels in specific neuronal cell types where LIM-HD proteins of the Isl class are synthesized. The overexpression of a dominant-negative CLIM molecule (DN-CLIM) that contains the LIM interaction domain (LID) during early developmental stages of zebrafish embryos results in an impairment of eye and midbrain-hindbrain boundary (MHB) development and disturbances in the formation of the anterior midline. On a cellular level we show that the outgrowth of peripheral but not central axons from Rohon Beard (RB) and trigeminal sensory neurons is inhibited by DN-CLIM overexpression. We demonstrate a further critical role of CLIM cofactors for axonal outgrowth of motor neurons. Additionally, DN-CLIM overexpression causes an increase of Isl-protein expression levels in specific neuronal cell types, likely due to a protection of the DN-CLIM/LIM-HD complex from proteasomal degradation. Our results demonstrate multiple roles of the CLIM cofactor family for the development of entire organs, axonal outgrowth of specific neurons and protein expression levels.
Zentrum für Molekulare Neurobiologie Hamburg, Universität Hamburg, Martinistrasse 85, 20251 Hamburg, Germany.
Thomas
T
Becker
Heather P
HP
Ostendorff
Michael
M
Bossenz
Anne
A
Schlüter
Catherina G
CG
Becker
Reto I
RI
Peirano
Ingolf
I
Bach
D000818:Animals; D001369:Axons / Q000378:metabolism / Q000648:ultrastructure; D001921:Brain / Q000196:embryology / Q000378:metabolism; D005123:Eye / Q000196:embryology / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D005801:Genes, Homeobox; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D009474:Neurons / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*
D018398:Homeodomain Proteins; D014157:Transcription Factors