Journal of Genetics and Genomics

A functional missense variant in ITIH3 affects protein expression and neurodevelopment and confers schizophrenia risk in the Han Chinese population

Kaiqin Li, Yifan Li, Junyang Wang, Yongxia Huo, Di Huang, Shiwu Li, Jiewei Liu, Xiaoyan Li, Rong Liu, Xiaogang Chen, Yong-Gang Yao, Ceshi Chen, Xiao Xiao, Ming Li, Xiong-Jian Luo

2020, 47(5): 233-248. doi: 10.1016/j.jgg.2020.04.001

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Abstract:
The Psychiatric Genomics Consortium (PGC) has recently identified 10 potential functional coding variants for schizophrenia. However, how these coding variants confer schizophrenia risk remains largely unknown. Here, we investigate the associations between eight potential functional coding variants identified by PGC and schizophrenia in a large Han Chinese sample (n = 4022 cases and 9270 controls). Among the eight tested single nucelotide polymorphisms (SNPs), rs3617 (a missense variant, p.K315Q in the ITIH3 gene) showed genome-wide significant association with schizophrenia in the Han Chinese population (P = 8.36 × 10⁻¹⁶), with the same risk allele as in PGC. Interestingly, rs3617 is located in a genomic region that is highly evolutionarily conserved, and its schizophrenia risk allele (C allele) was associated with lower ITIH3 mRNA and protein expression. Intriguingly, mouse neural stem cells stably overexpressing ITIH3 with different alleles of rs3617 exhibited significant differences in proliferation, migration, and differentiation, suggesting the impact of rs3617 on neurodevelopment. Subsequent transcriptome analysis found that the differentially expressed genes in neural stem cells stably overexpressing different alleles of rs3617 were significantly enriched in schizophrenia-related pathways, including cell adhesion, synapse assembly, MAPK and PI3K-AKT pathways. Our study provides convergent lines of evidence suggesting that rs3617 in ITIH3 likely affects protein function and neurodevelopment and thereby confers risk of schizophrenia.

Generation of rat blood vasculature and hematopoietic cells in rat-mouse chimeras by blastocyst complementation

Xiaomin Wang, Hui Shi, Juanjuan Zhou, Qingjian Zou, Quanjun Zhang, Shixue Gou, Pengfei Chen, Lisha Mou, Nana Fan, Yangyang Suo, Zhen Ouyang, Chengdan Lai, Quanmei Yan, Liangxue Lai

2020, 47(5): 249-261. doi: 10.1016/j.jgg.2020.05.002

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Abstract:
Interspecies chimera through blastocyst complementation could be an alternative approach to create human organs in animals by using human pluripotent stem cells. A mismatch of the major histocompatibility complex of vascular endothelial cells between the human and host animal will cause graft rejection in the transplanted organs. Therefore, to achieve a transplantable organ in animals without rejection, creation of vascular endothelial cells derived from humans within the organ is necessary. In this study, to explore whether donor xeno-pluripotent stem cells can compensate for blood vasculature in host animals, we generated rat-mouse chimeras by injection of rat embryonic stem cells (rESCs) into mouse blastocysts with deficiency of Flk-1 protein, which is associated with endothelial and hematopoietic cell development. We found that rESCs could differentiate into vascular endothelial and hematopoietic cells in the rat-mouse chimeras. The whole yolk sac (YS) of Flk-1 rat-mouse chimera was full of rat blood vasculature. Rat genes related to vascular endothelial cells, arteries, and veins, blood vessels formation process, as well as hematopoietic cells, were highly expressed in the YS. Our results suggested that rat vascular endothelial cells could undergo proliferation, migration, and self-assembly to form blood vasculature and that hematopoietic cells could differentiate into B cells, T cells, and myeloid cells in rat-mouse chimeras, which was able to rescue early embryonic lethality caused byFlk-1 deficiency in mouse.

CRISPR/Cas9-mediated disruption of TaNP1 genes results in complete male sterility in bread wheat

Jian Li, Zheng Wang, Guangming He, Ligeng Ma, Xing Wang Deng

2020, 47(5): 263-272. doi: 10.1016/j.jgg.2020.05.004

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Abstract:
Male sterile genes and mutants are valuable resources in hybrid seed production for monoclinous crops. High genetic redundancy due to allohexaploidy makes it difficult to obtain the nuclear recessive male sterile mutants through spontaneous mutation or chemical or physical mutagenesis methods in wheat. The emerging effective genome editing tool, CRISPR/Cas9 system, makes it possible to achieve simultaneous mutagenesis in multiple homoeoalleles. To improve the genome modification efficiency of the CRISPR/Cas9 system in wheat, we compared four different RNA polymerase (Pol) III promoters (TaU3p, TaU6p, OsU3p, and OsU6p) and three types of sgRNA scaffold in the protoplast system. We show that theTaU3 promoter-driven optimized sgRNA scaffold was most effective. The optimized CRISPR/Cas9 system was used to edit three TaNP1 homoeoalleles, whose orthologs, OsNP1 in rice and ZmIPE1 in maize, encode a putative glucose-methanol-choline oxidoreductase and are required for male sterility. Triple homozygous mutations in TaNP1 genes result in complete male sterility. We further demonstrated that any one wild-type copy of the three TaNP1 genes is sufficient for maintenance of male fertility. Taken together, this study provides an optimized CRISPR/Cas9 vector for wheat genome editing and a complete male sterile mutant for development of a commercially viable hybrid wheat seed production system.

Investigation of CRISPR/Cas9-induced SD1 rice mutants highlights the importance of molecular characterization in plant molecular breeding

Sukumar Biswas, Jiaqi Tian, Rong Li, Xiaofei Chen, Zhijing Luo, Mingjiao Chen, Xiangxiang Zhao, Dabing Zhang, Staffan Persson, Zheng Yuan, Jianxin Shi

2020, 47(5): 273-280. doi: 10.1016/j.jgg.2020.04.004

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Abstract:
Although Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated 9 (Cas9) system has been widely used for basic research in model plants, its application for applied breeding in crops has faced strong regulatory obstacles, due mainly to a poor understanding of the authentic output of this system, particularly in higher generations. In this study, different from any previous studies, we investigated in detail the molecular characteristics and production performance of CRISPR/Cas9-generated SD1 (semi-dwarf 1) mutants from T₂ to T₄ generations, of which the selection of T₁ and T₂ was done only by visual phenotyping for semidwarf plants. Our data revealed not only on- and off-target mutations with small or lager indels but also exogenous elements in T₂ plants. All indel mutants passed stably to T₃ or T₄ without additional modifications independent on the presence of Cas9, while some lines displayed unexpected hereditary patterns of Cas9 or some exogenous elements. In addition, effects of various SD1 alleles on rice height and yield differed depending on genetic backgrounds. Taken together, our data showed that the CRISPR/Cas9 system is effective in producing homozygous mutants for functional analysis, but it may be not as precise as expected in rice, and that early and accurate molecular characterization and screening must be carried out for generations before transitioning of the CRISPR/Cas9 system from laboratory to field.

A novel pathogenic mutation in FBN2 associated with congenital contractural arachnodactyly for preimplantation genetic diagnosis

Jiaxin Li, Yuqian Wang, Xiaohui Zhu, Yanli Nie, Ying Kuo, Shuo Guan, Jin Huang, Ying Lian, Yangyu Zhao, Rong Li, Yuan Wei, Jie Qiao, Liying Yan

2020, 47(5): 281-284. doi: 10.1016/j.jgg.2020.03.007

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Abstract:

Dissection of the genetic mechanisms underlying congenital anal atresia in pigs

Kai Jiang, Yuyun Xing, Pan Xu, Qiang Yang, Chuanmin Qiao, Weiwei Liu, Hao Chen, Yuyong He, Jun Ren, Lusheng Huang

2020, 47(5): 285-288. doi: 10.1016/j.jgg.2020.05.003

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Abstract:

2020 Vol. 47, No. 5