Hetrin基因在大鼠脑发育过程中表达的初步研究

本文目的是 :观察 hetrin基因在大鼠脑发育过程中的表达变化规律 ,藉以探讨 hetrin在神经系统发育过程中的作用。以地高辛 (dig)标记 hetrin基因 3 ' -末端 c RNA为探针 ,采用原位杂交法研究 hetrin m RNA在生后第 10 d(P10 )、P3 0和 P60大鼠脑中的分布状况 ;同时采用半定量 RT-PCR法分析出生前后大鼠脑内 hetrin m RNA表达水平的变化。结果发现 ,hetrin m RNA原位杂交阳性信号定位于神经元胞质内 ,在 P10、P3 0和 P60大鼠的脑组织中均可见明显的杂交信号。 RT-PCR结果显示 ,在胚胎第 9d(E9)大鼠脑内 hetrin m RNA开始表达 ,但表达量很低 ,以后其表达量逐渐升高。出生后大鼠不同脑区 hetrin m RNA的表达量变化趋势不同。本实验结果表明 ,在胚胎期及出生后大鼠脑的多个部位都有 hetrin m RNA表达 ,而且 hetrin m RNA表达量与神经细胞突起生长及新突触连接的建立在时间上有一定的同步性 ,提示 hetrin m RNA的表达与神经突起生长存在着一定的关系 ,进一步支持存在 hetrin基因的神经细胞突起具有诱向生长功能

A DEVELOPMENTAL STUDY ON THE EXPRESSION OF HETRIN mRNA IN RAT BRAIN

To observe hetrin gene expression during development of rat brain, the expression of hetrin mRNA in rat brain was examined by in situ hybridization with digoxin labeled cRNA probe for the 3' terminal part of hetrin mRNA. Reverse transcription polymerase chain reaction (RT PCR) method was also used to investigate the expression level of hetrin mRNA in brain during development. Strong hybridized signals of hetrin mRNA were found in the cytoplasm of neuron. The positive signals of hetrin mRNA were detected in postnatal 10th day, 30th day and 60th day of rat brain. From the results of RT PCR, expression level of hetrin mRNA in rat appeared with a lower level on embryonic 9th day. After this, it increased gradually. In postnatal rat, the expression of hetrin mRNA had different patterns in different tissues but was almost kept at a relative high level. As the expression of hetrin mRNA had an overlapped time phase change with the outgrowth of neurite and the formation of new synapses, our results strongly support the known axon guidance function of hetrin in the development of rat brain.