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.

Regulations in the EU, Japan, Korea, etc. require that foods and feeds made of or derived from genetically modified organisms (GMOs) should be approved and labeled according to a threshold. Recently, disease resistant transgenic rice was developed in Korea, which resulted from the transformation events involving choline kinase gene, OsCK1. In order to monitor unintended release of the developed GM rice in the near future, as well as to meet GM-labeling requirements, the development of a reliable method for detection of disease resistant GM rice is requisite. Here, specific primer pairs for the detection of GMO was designed on the basis of a introduced gene and the flanking junction sequences between a plant DNA and a integrated gene construct, and also SPS gene was used as an endogenous reference material. Specificities of all designed primers were tested through qualitative PCRs. Clearly, target specific amplicons could be detected from disease resistant GM rice event. In addition, the limits of detection (LOD) using the event-specific primers were approximately 0.1% for the disease resistant GM rice line. This result indicated that the developed detection method is suitable for the traceability of disease resistant GM rice, because of using the primer specifically corresponded to the junction site between plant genomic DNA and inserted DNA. Keywords: genetically modified organisms, disease resistant GM rice, PCR detection, event-specific primer