碩士 / 國立臺灣大學 / 漁業科學研究所 / 101 / The mammalian oxytocin homolog in teleost fish, isotocin (itnp), was previously shown to play a major role on the proliferation of epidermal stem cells. However, the involvement of isotocin receptor in the isotocin control pathways of fish ionic and osmotic regulation through the epidermal ionocytes is unknown. In the present study, the roles of isotocin-isotocin neurophysin receptor (itnpr) axis in the epidermal cells development were elucidated using zebrafish as the animal model.
Loss of function assay using morpholino oligos showed that itnp morphants significantly decreased epidermal stem cells (p63-positive cell), matured ionocytes (Na+-K+-ATPase-rich cells: NaRC and H+-ATPase-rich cells: HRC), and keratinocytes numbers significantly decreased. In addition, itnp cRNA over-expression increased epidermal stem cells number. These show profound effects of itnp in epidermal
development through the stem cell. Using quantitative PCR, itnpr1 mRNA decreased significantly in the itnp morphants cDNA templates, but itnpr2 increased. This indicates
itnpr1 and 2 have opposite functions. As confirmed by the knockdown, itnpr1 morphants showed significant increase in stem cells, matured ionocytes and keratinocytes number, whereas loss of itnpr2 has reverse effects. Gain of function
showed that itnpr1 cRNA and itnpr2 cRNA-injected embryos reversed the results in MO injection alone with stem cells results. These data demonstrated that itnpr1 and 2 play opposite roles in fish epidermal development.
To further understand the function of these receptors, series of co-injection experiments were performed. Double knockdown of itnpr1 and r2 showed no significant
effect to the control morphants. The density of stem cell increased in itnpr1-MO plus r2-cRNA but decreased in itnpr2-MO plus r1-cRNA-injected embryos. These data further demonstrated that these two receptors play opposite role and restrict each others actions.
In case of mucous cells, itnp morphants showed increased in density, but decreased in both of receptors morphants. These may show that other factors influences mucous cell development independent from the known stem cell lineage pathway.
Altogether, itnp-itnprs system shows to play an important role in zebrafish epidermal cell development. The effect of itnpr1 (negative) is in contrast to itnpr2
(positive) on regulating epidermal cells number. These opposite roles could be a feedback regulation, which is a physiological need to facilitate proper epidermal cell
development and maintain the iono/osmo balance in zebrafish. Hence, this study provides new knowledge and platform to better understand the specific roles of itnpr1
and r2 in fish epidermal development.
| Identifer | oai:union.ndltd.org:TW/101NTU05451005 |
| Date | January 2012 |
| Creators | Hsin-Hui Kan, 甘馨惠 |
| Contributors | Pung-Pung Wang, 黃鵬鵬 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 62 |
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