Cysteine-rich transmembrane bone morphogenetic protein regulator 1 (CRIM1) is a type I transmembrane protein involved in the organogenesis of many tissues via its interactions with growth factors including BMP, TGF-β, and VEGF. In this study, we used whole-exome sequencing and linkage analysis to identify a novel Crim1 mutant allele generated by ENU mutagenesis in mice. This allele is a missense mutation that causes a cysteine-to-serine substitution at position 140, and is referred to as Crim1C140S. In addition to the previously reported phenotypes in Crim1 mutants, Crim1C140S homozygous mice exhibited several novel phenotypes, including dwarfism, enlarged seminal vesicles, and rectal prolapse. In vitro analyses showed that Crim1C140S mutation affected the formation of CRIM1 complexes and decreased the amount of the overexpressed CRIM1 proteins in the cell culture supernatants. Cys140 is located in the internal region 1 (IR1) of the N-terminal extracellular region of CRIM1 and resides outside any identified functional domains. Inference of the domain architecture suggested that the Crim1C140S mutation disturbs an intramolecular disulfide bond in IR1, leading to the protein instability and the functional defects of CRIM1. Crim1C140S highlights the functional importance of the IR1, and Crim1C140S mice should serve as a valuable model for investigating the functions of CRIM1 that are unidentified as yet.

中文翻译：

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Crim1C140S突变小鼠揭示CRIM1的内部区域1中的半胱氨酸140对其生理功能的重要性。

富含半胱氨酸的跨膜骨形态发生蛋白调节剂1（CRIM1）是I型跨膜蛋白，它通过与生长因子（包括BMP，TGF-β和VEGF）的相互作用而参与许多组织的器官发生。在这项研究中，我们使用全外显子组测序和连锁分析来鉴定由ENU诱变在小鼠中产生的新型Crim1突变体等位基因。该等位基因是一种错义突变，会在位置140处引起半胱氨酸到丝氨酸的取代，被称为Crim1C140S。除了先前报告的Crim1突变体表型外，Crim1C140S纯合小鼠还表现出几种新颖的表型，包括侏儒症，精囊增大和直肠脱垂。体外分析表明，Crim1C140S突变影响了CRIM1复合物的形成，并减少了细胞培养上清液中过表达的CRIM1蛋白的量。Cys140位于CRIM1的N末端胞外区的内部区域1（IR1），并且位于任何已识别的功能域之外。域结构的推断表明，Crim1C140S突变干扰IR1中的分子内二硫键，从而导致蛋白质不稳定和CRIM1的功能缺陷。Crim1C140S强调了IR1的功能重要性，而Crim1C140S小鼠应作为有价值的模型，用于研究尚未鉴定的CRIM1的功能。Cys140位于CRIM1的N末端胞外区的内部区域1（IR1），并且位于任何已识别的功能域之外。域结构的推断表明，Crim1C140S突变干扰IR1中的分子内二硫键，从而导致蛋白质不稳定和CRIM1的功能缺陷。Crim1C140S突出了IR1的功能重要性，而Crim1C140S小鼠应作为研究CRIM1尚未被鉴定的功能的有价值的模型。Cys140位于CRIM1的N末端胞外区的内部区域1（IR1）中，并且位于任何已识别的功能域之外。域结构的推断表明，Crim1C140S突变干扰IR1中的分子内二硫键，从而导致蛋白质不稳定和CRIM1的功能缺陷。Crim1C140S突出了IR1的功能重要性，而Crim1C140S小鼠应作为研究CRIM1尚未被鉴定的功能的有价值的模型。