Zebrafish as a model organism for the study of functional genomics
Chih-Ming Chou 1, Yueh-Chun Hsieh2, I-Ching Lu2, Juei-Pei Chang2, Mei-Chen
Tseng2, and Chang-Jen Huang2,*
1
2
Department of Biochemistry, Taipei Medical University, Taipei, Taiwan, Institute of
Biological Chemistry, Academia Sinica, Taipei, Taiwan.
In order to investigate the functional roles of novel genes in vertebrates, the
generation of transgenic or gene knock-out mice has been wildly established.
However, it is an expensive and time-consuming process that cannot be applicable to
other vertebrate species. Zebrafish is a good model organism for the study of
vertebrate development. The embryos develop outside the mother and are optically
transparent, allowing direct observation of their embryonic development that takes
only 48 hours for completion at 280C. Currently, more than 6 biotech companies in
USA use zebrafish to develop models for human disease and to screen small
molecules.
We have cloned several zebrafish tissue-specific promoters including heart-,
pancreatic-, neuron-, skin-, muscle- blood vessel- and intestine-specific promoters.
Their tissue specificies of gene expression were confirmed by expression of GFP in
zebrafish embryos. Therefore, these tissue-specific promoters could be used to drive
GFP or RFP expression in zebrafish embryos. Some transgenic GFP/RFP zebrafishes
have been established while others will be established in the future.
In general, it is common to investigate the function of known or novel genes by
gain of function and loss of function in zebrafish. To achieve the functional study by
gain of function, genes of interest are driven by tissue-specific promoters and injected
into one-cell zebrafish embryos. Alternatively, the expression constructs under the
control of either ubiquitous or tissue-specific promoter were coinjected with
tissue-specific promoter/GFP construct. On the other hand, to achieve the functional
study by loss of function, genes of interest are knockdowned by injection of
morpholino antisense-oligomnucleotides (MAO) or coinjection of MAO and
tissue-specific promoter/GFP construct. Some examples relating to gain of function
and loss of function in zebrafish by the approach mentioned above will be presented
in the seminar.