Dr. Shuk Han CHENG

2004年07月16日(金) 16:00 より 17:30 まで

明大寺地区１階会議室（１１１）

形態形成研究部門 上野 直人 内線7570 nueno@nibb.ac.jp

Appropriate temporal and spatial expression of genes is important for normal development of embryo. Ectopic gene expression is often associated with organ malformations and even embryonic deaths. The major criteria of quantification of gene expression include the localization of the expression domains in the topographical context of a tissue,and the distinction between alterations in expression level and the number of expressing cells. In our laboratory we develop biocomputational tools to perform 3D and 4D quantification of gene expression in zebrafish embryos. Confocal images of fluorescent in situ hybridized embryos were used to reconstruct the gene expression domains with topographical intact morphology in 3D quantification. Gene expression was quantified by measuring total number of fluorescent pixels (proportional to number of expressing cells) and their average fluorescent intensity (proportional to expression level). To remove fluorescent signals from the background, we developed a novel thresholding algorithm to estimate the density function of each pixel. Using cadmium chloride exposure as an example, we showed that total fluorescent intensity of ngn-1 was reduced but the average fluorescent intensity was not affected, indicating that cadmium chloride reduced the number of ngn-1 expressing cells but did not affect the level of ngn-1 expression. The results are consistent with our previous study which showed that the number of trigeminal ganglia, which was regulated by ngn-1 expression, was reduced in cadmium chloride-treated zebrafish embryos