Characterizing the functions of a microcephaly-related gene in a knock-out mouse model using in vivo MRI, histology and cellular/molecular biology app

人类运输蛋白颗粒复合体亚单位9‘(TRAPPC9)基因的突变会导致小头畸形、智力残疾、语言障碍和发育迟缓。该蛋白在细胞内转运和囊泡大小的调节中起作用。在这个项目中，我们将使用一个新的TRAPPC9 KO系作为我们的初步未发表数据，通过高分辨率磁共振成像(显微镜MRI)测量大脑重量和脑体积，证实年轻成年突变人患有小头畸形。我们描述了TRAPPC9在大脑的神经元和神经前体细胞(NPC)子集以及神经球培养中的表达模式。我们发现在海马齿状回中SOX2阳性的神经前体细胞减少，但其他成人神经源性区域尚未被研究。目的1：用MRI和组织学方法评价TRAPPC9缺陷脑的异常，并确定小头畸形的发育期。由于小头症的发育期尚不清楚，我们将进行一项纵向的活体MRI研究，以检测出生后和幼年不同阶段的总脑体积。目标2：体内和体外神经前体细胞的功能评估，并确定原代神经元培养中囊泡运输和亚细胞区段的缺陷。在体外，我们将使用神经球培养来评估鼻咽癌的增殖和分化。

Mutations in the human 'Trafficking protein particle complex subunit 9' (TRAPPC9) gene cause microcephaly, intellectual disability, speech impairment and developmental delays. The protein functions in the regulation of intracellular transport and vesicle size. In this project we will use a novel Trappc9 KO line as our preliminary unpublished data confirms microcephaly in young adult mutants through measurements of brain weights as well as brain volumes via high-resolution magnetic resonance imaging (microscopic MRI). We characterised the Trappc9 expression pattern in a subset of neurons and neural progenitor cells (NPCs) of the brain and in neurosphere cultures. We found a reduction in Sox2-positive NPCs in the hippocampal dentate gyrus, but other adult neurogenic regions have not yet been investigated. Objective 1: Evaluation of abnormalities in Trappc9 deficient brains using MRI and histology, and determination of the developmental onset of microcephaly. Since the developmental onset of microcephaly is unclear, we will undertake a longitudinal in vivo MRI study to examine total brain volumes at various postnatal and juvenile stages.Objective 2: Functional assessment of neural progenitor cells in vivo and ex vivo, and determination of deficiencies in vesicle transport and sub-cellular compartments in primary neuronal cultures. Ex vivo, we will assess NPC proliferation and differentiation using neurosphere cultures.