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The ascidian numb gene involves in the formation of neural tissues.

Ahn HR, Kim GJ - (2012)

Bottom Line: Its zygotic expression became evident by the early neurula stage and the transcripts were detected in dorsal neural precursor cells.Similar results have been obtained by overexpression of the constitutively activated Hr-Notch forms.Therefore, these results suggest that Hr-Numb is involved in Notch signaling during ascidian embryogenesis.

View Article: PubMed Central - PubMed

Affiliation: Present address: Functional Food Center, Korea Institute of Science and Technology, Gangneung Institute, Gangneung 210-340, Korea.

ABSTRACT
Notch signaling plays fundamental roles in various animal development. It has been suggested that Hr-Notch, a Notch homologue in the ascidian Halocynthia roretzi, is involved in the formation of peripheral neurons by suppressing the neural fates and promoting the epidermal differentiation. However, roles of Notch signaling remain controversial in the formation of nervous system in ascidian embryos. To precisely investigate functions of Notch signaling, we have isolated and characterized Hr-Numb, a Numb homologue which is a negative regulator of Notch signaling, in H. roretzi. Maternal expression of Hr-Numb mRNAs was detected in egg cytoplasm and the transcripts were inherited by the animal blastomeres. Its zygotic expression became evident by the early neurula stage and the transcripts were detected in dorsal neural precursor cells. Suppression of Hr-Numb function by an antisense morpholino oligonucleotide resulted in larvae with defect in brain vesicle and palps formation. Similar results have been obtained by overexpression of the constitutively activated Hr-Notch forms. Therefore, these results suggest that Hr-Numb is involved in Notch signaling during ascidian embryogenesis.

No MeSH data available.


Related in: MedlinePlus

The nucleotide and deduced amino acid sequences of a cDNA clone for the Hr-Numb. The sequence of the cDNA encompasses 1,624 bp including 5’ and 3’untranslational regions. The ATG at the position 47-49 represents the putative start codon of the Hr-Numb-encoded protein of 456 amino acids. The termination codon is shown by an asterisk and the PTB domain is underlined. The 25 base pairs for MO design are shown by dotted lines around the putative start codon.
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Figure 1: The nucleotide and deduced amino acid sequences of a cDNA clone for the Hr-Numb. The sequence of the cDNA encompasses 1,624 bp including 5’ and 3’untranslational regions. The ATG at the position 47-49 represents the putative start codon of the Hr-Numb-encoded protein of 456 amino acids. The termination codon is shown by an asterisk and the PTB domain is underlined. The 25 base pairs for MO design are shown by dotted lines around the putative start codon.

Mentions: To clarify the mechanism by which Notch signaling specify neural cells during ascidian embryogenesis, we isolated Numb homologue (Hr-Numb) in the ascidian Halocynthia roretzi by the classical RT-PCR and 5’ and 3’ RACE. In various Numb proteins, the N-terminal region, which contains the phosphotyrosine-binding (PTB) domain interacting with a wide variety of different proteins, is highly conserved among vertebrates and invertebrates (Berdnik et al., 2002; Reugels et al., 2006). Using degenerate oligonucleotide primers (see Materials and Methods), we amplified target fragments from the Halocynthia gastrula stage poly(A) RNA by RT-PCR. Then, a fragment of Halocynthia Numb covering the complete ORF was obtained by RACE. A cDNA clone for Hr-Numb was 1,624 base pairs in full length, and the predicted protein has 456 amino acids (Fig. 1). The predicted amino acid sequence contained a well-conserved N-teminus sequence between various Numb homologues. Although the over degree of amino acid identity was not high (about ~ 30%), the amino acid sequence of Hr-Numb PTB domain was highly conserved when compared with the PTB domains of other Numb proteins (data not shown).


The ascidian numb gene involves in the formation of neural tissues.

Ahn HR, Kim GJ - (2012)

The nucleotide and deduced amino acid sequences of a cDNA clone for the Hr-Numb. The sequence of the cDNA encompasses 1,624 bp including 5’ and 3’untranslational regions. The ATG at the position 47-49 represents the putative start codon of the Hr-Numb-encoded protein of 456 amino acids. The termination codon is shown by an asterisk and the PTB domain is underlined. The 25 base pairs for MO design are shown by dotted lines around the putative start codon.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4282237&req=5

Figure 1: The nucleotide and deduced amino acid sequences of a cDNA clone for the Hr-Numb. The sequence of the cDNA encompasses 1,624 bp including 5’ and 3’untranslational regions. The ATG at the position 47-49 represents the putative start codon of the Hr-Numb-encoded protein of 456 amino acids. The termination codon is shown by an asterisk and the PTB domain is underlined. The 25 base pairs for MO design are shown by dotted lines around the putative start codon.
Mentions: To clarify the mechanism by which Notch signaling specify neural cells during ascidian embryogenesis, we isolated Numb homologue (Hr-Numb) in the ascidian Halocynthia roretzi by the classical RT-PCR and 5’ and 3’ RACE. In various Numb proteins, the N-terminal region, which contains the phosphotyrosine-binding (PTB) domain interacting with a wide variety of different proteins, is highly conserved among vertebrates and invertebrates (Berdnik et al., 2002; Reugels et al., 2006). Using degenerate oligonucleotide primers (see Materials and Methods), we amplified target fragments from the Halocynthia gastrula stage poly(A) RNA by RT-PCR. Then, a fragment of Halocynthia Numb covering the complete ORF was obtained by RACE. A cDNA clone for Hr-Numb was 1,624 base pairs in full length, and the predicted protein has 456 amino acids (Fig. 1). The predicted amino acid sequence contained a well-conserved N-teminus sequence between various Numb homologues. Although the over degree of amino acid identity was not high (about ~ 30%), the amino acid sequence of Hr-Numb PTB domain was highly conserved when compared with the PTB domains of other Numb proteins (data not shown).

Bottom Line: Its zygotic expression became evident by the early neurula stage and the transcripts were detected in dorsal neural precursor cells.Similar results have been obtained by overexpression of the constitutively activated Hr-Notch forms.Therefore, these results suggest that Hr-Numb is involved in Notch signaling during ascidian embryogenesis.

View Article: PubMed Central - PubMed

Affiliation: Present address: Functional Food Center, Korea Institute of Science and Technology, Gangneung Institute, Gangneung 210-340, Korea.

ABSTRACT
Notch signaling plays fundamental roles in various animal development. It has been suggested that Hr-Notch, a Notch homologue in the ascidian Halocynthia roretzi, is involved in the formation of peripheral neurons by suppressing the neural fates and promoting the epidermal differentiation. However, roles of Notch signaling remain controversial in the formation of nervous system in ascidian embryos. To precisely investigate functions of Notch signaling, we have isolated and characterized Hr-Numb, a Numb homologue which is a negative regulator of Notch signaling, in H. roretzi. Maternal expression of Hr-Numb mRNAs was detected in egg cytoplasm and the transcripts were inherited by the animal blastomeres. Its zygotic expression became evident by the early neurula stage and the transcripts were detected in dorsal neural precursor cells. Suppression of Hr-Numb function by an antisense morpholino oligonucleotide resulted in larvae with defect in brain vesicle and palps formation. Similar results have been obtained by overexpression of the constitutively activated Hr-Notch forms. Therefore, these results suggest that Hr-Numb is involved in Notch signaling during ascidian embryogenesis.

No MeSH data available.


Related in: MedlinePlus