23 days old 2310061I04Rik-null brain transcriptome

Here, we describe a spontaneous mouse mutant with a deletion in a predicted gene 2310061I04Rik (Rik) of unknown function located on chromosome 17. A 59 base pair long deletion occurred in the first intron of the Rik gene and disrupted its expression. Riknull mice were born healthy and appeared anatomically normal up to two weeks of age. After that, these mice showed inhibited growth, ataxic gait, and died shortly after postnatal day 24 (P24). Transcriptome analysis at P14 and P23 revealed significantly reduced expression of mitochondrial genes in Riknull brains compared to wild type controls including mt-Nd4, mt-Cytb, mt-Nd2, mt-Co1, mt-Atp6, and others. Similarly, genes specific for myelinating oligodendrocytes also showed reduced expression in P23 Riknull brains compared to controls. Histological examination of anterior thalamic nuclei demonstrated decreased myelination of anteroventral nuclei but not of anterodorsal nuclei in P23 Riknull mice. Myelination of the anterior commissure was also impaired and displayed extensive vacuolation. Consistently with these findings, immunohistochemistry showed reduced expression of Opalin, a glycoprotein expressed in differentiated oligodendrocytes. Taken together, these results suggest that RIK is important for oligodendrocyte maturation and myelination in the developing brain. Brain collected at P23 and placed in RNAlater. Half of the brain (sagittal cut down midline) sent to Novogene for processing.本研究描述了一种自发产生的小鼠突变体，其位于17号染色体上、功能未知的预测基因2310061I04Rik（简称Rik）存在片段缺失。该突变体的Rik基因第一内含子区域存在一段59碱基对的缺失，该缺失破坏了该基因的表达。Rik基因敲除（Riknull）小鼠出生时状态健康，且在出生后两周内解剖结构均表现正常。两周后，该类小鼠出现生长受抑、共济失调步态，并在出生后第24天（P24）左右死亡。对出生后第14天（P14）和第23天（P23）的样本进行转录组分析显示，与野生型对照组相比，Riknull小鼠脑组织中线粒体基因（包括mt-Nd4、mt-Cytb、mt-Nd2、mt-Co1、mt-Atp6等）的表达水平显著下调。类似地，与对照组相比，P23阶段Riknull小鼠脑组织中特异性表达于髓鞘形成少突胶质细胞的基因表达水平同样出现下调。对P23阶段Riknull小鼠的丘脑前核进行组织学检查发现，其前腹侧丘脑核的髓鞘形成减少，而前背侧丘脑核无此变化。前连合的髓鞘形成同样受损，且出现广泛空泡化。与上述结果一致，免疫组化检测显示，在分化成熟的少突胶质细胞中表达的糖蛋白Opalin的表达水平降低。综上，上述结果表明RIK对于发育中大脑的少突胶质细胞成熟及髓鞘形成至关重要。于P23阶段采集脑组织并置于RNAlater保存液中。将脑组织沿矢状面中线切开分为两半，其中一半送至诺禾致源（Novogene）进行后续处理。