CNBP regulates forebrain formation at organogenesis stage in chick embryos

Abstract

We recently demonstrated that Cellular Nucleic acid Binding Protein (CNBP)(-/-) mouse embryos exhibit forebrain truncation due to a lack of proper morphogenetic movements of the anterior visceral endoderm (AVE) during pre-gastrulation stage (Chen, W., Liang, Y., Deng, W., Shimizu, K., Ashique, A.M., Li, E., Li, Y.P., 2003. The zinc-finger protein CNBP is required for forebrain formation in the mouse, Development 130, 1367-1379). However, CNBP expression pattern in the mouse forebrain suggests that CNBP may have more direct effects during forebrain development. Our data show that CNBP is expressed in tissues of early chick embryo that are the equivalent to the mouse embryo. Using a combination of RNAi-silencing and Retrovirus-misexpression approaches, we investigated the temporal function of CNBP in the specification/development of the chick forebrain during organogenesis. The silencing of CNBP expression resulted in forebrain truncation and the absence of BF-1, Six3 and Hesx1 expression, but not Otx2 in chick embryos. Misexpression of CNBP induced the expression of BF-1, Six3 and Hesx1 in the hindbrain, but not the expression of Otx2. These results offer novel insights into the function of CNBP during organogenesis as the regulator of forebrain formation and a number of rostral head transcription factors. Moreover, CNBP and Otx2 may play roles as regulators of forebrain formation in two parallel pathways. These new insights into CNBP functions underscore the essential role of CNBP in forebrain formation during chick embryo organogenesis.

Expression pattern of cellular nucleic acid-binding protein (CNBP) during embryogenesis and spermatogenesis of gibel carp

“…During organogenesis, the CagCNBP transcripts peak in midbrain and hindbrain of gibel carp larva, which is coincident with the reports in mouse and chick [12,13], but it has not been revealed in zebrafish [9]. Moreover, we find that the CagCNBP also predominantly expressed in tail somites, which is some similar with the predominant expression of CNBP in tail during chick embryogenesis [13].…”

“…During embryogenesis, the CNBP expression patterns have been analyzed in Bufo arenarum, Xenopus leavis, Danio rerio, mouse and chick [3,8,9,[11][12][13]. During early embryogenesis, CNBP mRNA could be detected in the The nucleotide sequence data reported in this paper have been submitted to the GenBank under accession number: CagCNBP (AY773183).…”

“…During early embryogenesis, CNBP mRNA could be detected in the The nucleotide sequence data reported in this paper have been submitted to the GenBank under accession number: CagCNBP (AY773183). unfertilized eggs and in the all embryonic cells in frog, zebrafish, cattle, chick and mouse [3,8,9,[11][12][13]. In mouse, during organogenesis, CNBP expresses predominantly in forebrain and midbrain, and plays important roles in cell proliferation and tissue patterning [12], and it is essential for the forebrain induction and specification [11].…”

“…In mouse, during organogenesis, CNBP expresses predominantly in forebrain and midbrain, and plays important roles in cell proliferation and tissue patterning [12], and it is essential for the forebrain induction and specification [11]. In chick, CNBP acts as a regulator of the forebrain formation in rostral head development during organogenesis by regulating other rostral head transcription factors [13]. In zebrafish, Armas et al have reported CNBP mRNA expression pattern in embryos from 2-cell stage to 26-somites stage [9], so its distribution and functional role during organogenesis in low vertebrates is still unclear.…”

Arginine methylation of the cellular nucleic acid binding protein does not affect its subcellular localization but impedes RNA binding

“…CNBP is highly conserved among human, mouse, rat, chicken, Xenopus species and fish [8]. The disruption of CNBP caused severe forebrain truncation and defective neural crest development [9][10][11].…”