Cystein-serine-rich nuclear protein 1, Axud1/Csrnp1, is essential for cephalic neural progenitor proliferation and survival in zebrafish.
The CSRNP (cystein-serine-rich nuclear protein) family has been conserved from Drosophila to human. Although knockout mice for each of the mammalian proteins have been generated, their function during vertebrate development has remained elusive. As an alternative to obtain insights on CSRNP's role in development, we have analysed the expression pattern and function of one member of this family, axud1, during zebrafish development. Our expression analysis indicates that axud1 is expressed from cleavage to larval stages in a dynamic pattern, becoming restricted after gastrulation to anterior regions of the developing neuraxis and later on concentrated predominantly in proliferating domains of the brain. Knockdown analysis using antisense morpholinos shows that reducing Axud1 levels impairs neural progenitor cell proliferation and survival, revealing an essential function of this gene for the growth of cephalic derivatives. The brain growth phenotypes elicited by decreasing Axud1 expression are specific and independent of anterior-posterior patterning events, initial establishment of neural progenitors, or neural differentiation occurring in this tissue. However, Axud1 is necessary for six3.1 expression and is positively regulated by sonic hedgehog. Phylogenetic examination shows that axud1 is likely to be the ortholog of the only member of this family present in Drosophila, as well as to the previously described mouse CSRNP1 and to human AXUD1 (Axin upregulated-1). Thus, we provide evidence as to the role of axud1 in brain growth in vertebrates.
Feijóo
Carmen G
CG
Center for Genomics of the Cell, Facultad de Ciencias, Universidad Chile, Santiago, Chile.
Sarrazin
Andres F
AF
Allende
Miguel L
ML
Glavic
Alvaro
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019521:Body Patterning / Q000235:genetics / Q000502:physiology; D001921:Brain / Q000166:cytology / Q000196:embryology*; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D018076:DNA, Complementary / Q000235:genetics; D053595:Embryonic Stem Cells / Q000166:cytology; D005136:Eye Proteins / Q000235:genetics / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018390:Gene Targeting; D053823:Hedgehog Proteins / Q000235:genetics / Q000502:physiology; D018398:Homeodomain Proteins / Q000235:genetics / Q000502:physiology; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000502:physiology; D009474:Neurons / Q000166:cytology; D009687:Nuclear Proteins / Q000235:genetics / Q000502:physiology*; D010802:Phylogeny; D017386:Sequence Homology, Amino Acid; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics / Q000502:physiology*; D029961:Zebrafish Proteins / Q000235:genetics / Q000502:physiology*; D000097607:Homeobox Protein SIX3
D018076:DNA, Complementary; D005136:Eye Proteins; D053823:Hedgehog Proteins; D018398:Homeodomain Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D029961:Zebrafish Proteins; D000097607:Homeobox Protein SIX3; C544776:csrnp1b protein, zebrafish