尖鼠牙齿发育中Shh与Bmp4基因的表达

Shh and Bmp4 expression in tooth development of Shew(Cryptotis parva)

目的观察生长因子Shh与Bmp4在尖鼠前磨牙乳恒牙发育中的基因表达情况。方法尖鼠胚胎于4%多聚甲醛中固定、脱水、包埋,制作8μm的石蜡切片,HE染色。通过美国国立图书馆Genbank数据库设计引物,克隆尖鼠Shh和Bmp4基因。制作35S放射性同位素标记探针进行原位杂交。结果观察到尖鼠上颌前磨牙不同时期的发育情况,E16天可见尖鼠乳前磨牙,之后恒牙开始发育,乳牙逐渐降解,至E21幼鼠出生时乳牙已完全降解,恒牙发育至钟状晚期。克隆出尖鼠Shh基因片段长210bp,Bmp4基因片段长626bp。它们在尖鼠乳前磨牙及恒前磨牙中均有表达,与小白鼠牙齿发育过程中的表达相似。结论生长因子Shh和Bmp4对牙齿发育而言是非常重要的两个因子,其作用相对保守。

Objective To study the expression of Shh and Bmp4 in tooth development of shrew （ Cryptotis parva） and to investigate the genetie regulation of premolar tooth morphogenesis. Methods The shrew embryos were fixed in 4% PFA ,dehydrated and embedded in paraffin. Serial sections were cut at 8μm, which were stained with haematoxylin and eosin. Shrew Shh and Bmp4 were amplified by RT-PCR using primers derived from Suneus murinus sequences found in the Genbank database. Radioactive section in situ hybridization with the use of ^35S-UTP radiolabeled riboprobes was made. Results The shrew upper deciduous premolar developed at cap stage in El6 ,which was gradually degenerated later on and permanent premolar started to develop. The deciduous premolar germ disappeared and permanent premolar was in later bell stage when shrew was born in E21. The shrew （ Cryptotis parva） Shh and Bmp4 partial CDNA were 210bp and 626bp,respectively. The expression patterns of Shh and Bmp4 in shrew premolar were the same as in mouse tooth development. Conclusion Shh and Bmp4 are very important for tooth development, and their functions are conserved in a certain extent.