14 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 P14 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突变小鼠，其17号染色体上存在功能未知的预测基因2310061I04Rik（简称Rik）的缺失突变。该突变位于Rik基因的第一内含子区域，包含一段59碱基对的缺失，进而破坏了该基因的表达。Riknull小鼠出生时状态健康，在出生后两周内解剖外观均无异常。在此之后，该类小鼠出现生长受抑、共济失调步态，并于出生后第24天（P24）左右死亡。对P14和P23时间点的脑组织进行转录组分析显示，与野生型对照相比，Riknull小鼠脑中的线粒体基因表达显著下调，包括mt-Nd4、mt-Cytb、mt-Nd2、mt-Co1、mt-Atp6等。同样，与对照组相比，P23时间点的Riknull小鼠脑中的髓鞘形成型少突胶质细胞特异性基因的表达也出现下调。对丘脑前核团的组织学检查显示，P23的Riknull小鼠的前腹侧丘脑核髓鞘形成减少，而前背侧丘脑核则无此异常。前连合的髓鞘形成同样受损，并出现广泛空泡化。与上述结果一致，免疫组化检测显示，在分化型少突胶质细胞中表达的糖蛋白Opalin的表达量显著降低。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具有关键作用。本研究采集了P14时间点的小鼠脑组织，置于RNAlater试剂中保存；将脑组织沿中线矢状切面分为两半，其中一半送往诺禾致源（Novogene）进行后续处理。