阅读说明：本技术 一种精神***症基因-基因互作网络及其构建方法 (Schizophrenia gene-gene interaction network and construction method thereof ) 是由 杨新平 高玥 梁小珍 任重鲁 李彦君 迟雅丽 于 2019-10-24 设计创作，主要内容包括：本发明公开了一种精神分裂症基因?基因互作网络的构建方法，所述构建方法包括以下步骤：①收集已知精神分裂症候选基因；②将上述收集的已知精神分裂症候选基因映射在人类蛋白质?蛋白质互作网络，转换成以基因命名的相互作用网络；③对网络中的所有基因进行R?score赋值，对网络中的所有基因进行G?score赋值，对每条边赋予权重；④构造节点间最短路径矩阵；以“游走扩展”法提取初步网络；⑤提取最终网络，输出结果。本发明构建精神分裂症基因?基因互作网络移除了部分假阳性基因，囊括进来了更多的与精神分裂症相关的潜在候选基因，富集分析结果表明，保留的基因与精神分裂症更相关，表明本发明构建的基因互作网络质量更优。(The invention discloses a method for constructing a gene-gene interaction network for schizophrenia, which comprises the following steps of ① collecting known schizophrenia candidate genes, ② mapping the collected known schizophrenia candidate genes on a human protein-protein interaction network to be converted into an interaction network named by genes, ③ carrying out R-score assignment on all genes in the network, carrying out G-score assignment on all genes in the network, giving weights to each edge, ④ constructing a shortest path matrix among nodes, extracting a preliminary network by a 'walking extension' method, ⑤ extracting a final network and outputting a result.)

1. A method for constructing a schizophrenia gene-gene interaction network is characterized by comprising the following steps of:

step ①, collecting known schizophrenia candidate genes from the database using bioinformatics methods;

step ②, mapping the collected known schizophrenia candidate genes on a human protein-protein interaction network, and converting the known schizophrenia candidate genes into an interaction network named by genes, wherein the network comprises the schizophrenia candidate genes and non-schizophrenia candidate genes, each gene is used as a node, and the signal path connecting lines between every two genes form the edges of the network;

step ③, assigning R-score to all genes in the network, assigning R-score to each schizophrenia candidate gene according to the frequency of occurrence of the schizophrenia candidate gene in different databases, wherein the R-score of the non-schizophrenia candidate genes is 0;

wherein R-score is 1-1.4^-XX is the number of times the gene is reported in the database of step ①, G-score is the average of the R-scores of the genes interacting with the gene, and the weight is the reciprocal of the sum of the two G-score values connected by the edge;

step ④, calculating and constructing the shortest path matrix between nodes by using distances in the R language igraph package according to the weight to obtain the shortest distance from each node to any node;

and ⑤, combining all the extracted nodes, extracting the final network by using Cytoscape, and outputting the result.

2. The method of constructing as claimed in claim 1, wherein said schizophrenia candidate gene in said step ① is obtained from a union of HGMD, SzGene, SzDB, SzGR, PheGenI, SNPedia and Literature databases.

3. The method of claim 1, wherein said human protein-protein interaction network of step ② is derived from the inBio Map database.

4. The method of claim 1, wherein said step ① is performed by using Cytoscape to map said collected genes of known schizophrenia symptoms onto a human protein-protein interaction network, and converting said genes into an interaction network named as genes.

5. The method of claim 1, wherein the step ④ is performed by using each schizophrenia candidate gene as a starting point, and expanding outward by using a step size of 0.5 as a radius, and if the ratio of candidate genes is significantly reduced for each expansion by 0.5 step size, the inner gene set is retained.

6. The construction method according to claim 1 or 5, wherein the final network is extracted in step ⑤ by extracting the network according to the parameters of candidate genes at a ratio of 85-90% and step size of 2.5-4.0, and removing the genes appearing in only one gene set.

7. The method of claim 6, wherein the candidate genes are present in a proportion of 90% in steps of 3.5.

8. A schizophrenia gene-gene interaction network constructed by the method as set forth in any one of claims 1 to 7.

Technical Field

The invention belongs to the technical field of biology, and particularly relates to a schizophrenia gene-gene interaction network and a construction method thereof.

Background

Schizophrenia is a heritable psychotic disorder, the disease characterized by positive and negative manifestations and symptoms and cognitive dysfunction that usually begins in early adulthood and usually persists for life. The focus of recent studies on schizophrenia has been mainly on the search for causative candidate genes, and these findings suggest that schizophrenia has a high degree of genetic heterogeneity.

The traditional method for searching risk genes in disease signaling pathway is to detect protein-protein interaction, such as the research on DISC1, but for schizophrenia with a large number of pathogenic genes, the function research on single gene one by one is not only inefficient, but also the information of mutual coordination and common action among genes can not be obtained. There are also some studies to map mutations on the KEGG signal pathway to find that risk genes are enriched in the cell adhesion molecular pathway, but the signal pathway does not act alone, and many other molecular pathways are involved, and the pathogenesis of most mutations is not clear at present, and the related pathogenesis pathway of schizophrenia caused by mutation of pathogenic candidate genes of schizophrenia has not been studied systematically.

It has been recognized that protein-protein interactions play a particularly important role in cellular molecular signaling pathway networks, and attempts have been made to study the molecular mechanisms of disease through the protein-protein interaction network of pathogenic genes. From a system biological perspective, disease risk genes for schizophrenia may act on a common molecular network, and such a common molecular network may involve multiple signaling pathways to perform related cellular functions. In 2013, people such as Gulsuner (Gulsuner, s., Walsh, t., Watts, a.c., Lee, m.k., Thornton, a.m., Casadei, s., Rippey, c., Shahin, h., Nimgaonkar, v.l., Go, r.c., Savage, r.m., Swerdlow, n.r., Gur, r.e., Braff, d.l., King, m.c., and McClellan, j.m. (2013) Spatial and temporal mapping of cardiac polypeptides in schizophyllan to a total transcriptional data of 154,518-529) showed mutual regulation of the functions of the genes of the new and normal brain regions of schizophrenic patients, and the transcriptional modules, which expressed and transported genes, expressed and expressed genes, and expressed by the neural modules of the neural networks, and the like, showed mutual regulation of the functions of the genes of the new and normal brain regions of schizophrenic patients. Such an integration analysis may infer possible functions of the mutated gene product, possibly in the brain and developmental stages that may be involved in the pathogenesis of the disease.

One of the functions of a gene existing in an organism is to translate a protein, and to express the activity of the protein, the phenotype of the organism is determined. In other words, the various traits of an organism are almost all the result of the interaction between genes, regulating the expression of each gene. The interaction between genes refers to the expression regulation relationship existing in different genes, generally, the expression product of one gene acts on another gene to influence the transcription and translation processes of another gene, and the interaction, interaction and mutual restriction relationship forms a gene interaction network.

Disclosure of Invention

The invention aims to provide a method for constructing a schizophrenia gene-gene interaction network.

In order to achieve the above purpose, the technical solution of the present invention is: a method for constructing a schizophrenia gene-gene interaction network comprises the following steps:

step ①, collecting known schizophrenia candidate genes from the database using bioinformatics methods;

step ②, mapping the collected known schizophrenia candidate genes on a human protein-protein interaction network, and converting the known schizophrenia candidate genes into an interaction network named by genes, wherein the network comprises the schizophrenia candidate genes and non-schizophrenia candidate genes, each gene is used as a node, and the signal path connecting lines between every two genes form the edges of the network;

step ③, assigning R-score to all genes in the network, assigning R-score to each schizophrenia candidate gene according to the frequency of occurrence of the schizophrenia candidate gene in different databases, wherein the R-score of the non-schizophrenia candidate genes is 0;

wherein R-score is 1-1.4^-XX is the number of times the gene is reported in the database of step ①, G-score is the average of the R-scores of the genes interacting with the gene, and the weight is the reciprocal of the sum of the two G-score values connected by the edge;

step ④, calculating and constructing the shortest path matrix between nodes by using distances in the R language igraph package according to the weight to obtain the shortest distance from each node to any node;

and ⑤, combining all the extracted nodes, extracting the final network by using Cytoscape, and outputting the result.

Preferably, the schizophrenia candidate gene in step ① is obtained from a union of HGMD, SzGene, SzDB, SzGR, PheGenI, SNPedia and Literature databases.

Preferably, the human protein-protein interaction network in step ② is derived from the inBio Map database.

Preferably, the known schizophrenia candidate genes collected as described above are mapped to a human protein-protein interaction network using Cytoscape in step ①, and converted into an interaction network named by gene.

Preferably, the specific method for extracting the preliminary network in step ④ is to use each schizophrenia candidate gene as a starting point, and expand outward by using step size 0.5 as a radius, and if the ratio of candidate genes is significantly reduced every 0.5 step size expansion, the inner gene set is retained.

Preferably, the specific method for extracting the final network in step ⑤ is to extract the network according to the parameters with the candidate gene ratio of 85-90% and the step size of 2.5-4.0, and simultaneously remove the genes only appearing in one gene set.

Preferably, the candidate gene ratio is 90% and the step size is 3.5.

In addition, another object of the present invention is to provide a schizophrenia gene-gene interaction network constructed by the above method.

Compared with the prior art, the invention has the following beneficial effects:

compared with the traditional method, the method for constructing the gene-gene interaction network of schizophrenia has more advantages, the extracted network removes part of false positive genes in the disclosed gene for selecting schizophrenia, more potential candidate genes related to schizophrenia are included, and the enrichment analysis result shows that the retained genes are more related to schizophrenia, thereby showing that the quality of the gene interaction network constructed by the method is better.

Drawings

FIG. 1 is a schematic diagram of a "wandering expansion method" for extracting a network;

FIG. 2 is a comparison of retention and removal of genes to enrich for differentially expressed genes in schizophrenia;

FIG. 3 is a comparison of retention and removal of genes to enrich for schizophrenia mutant genes;

FIG. 4 is a comparison of genes for retention and removal of genes to enrich for brain-specific expressed genes;

FIG. 5 is a comparison of tissue-specific gene enrichment for gene retention and gene removal.

Detailed description of the preferred embodiments

The present invention will be described in further detail below with reference to specific embodiments of examples. It should not be understood that the scope of the above-described subject matter of the present invention is limited to the following examples.

For a better understanding of the invention, the following explanations and illustrations are provided:

HGMD: called Human Gene Mutation Database (Human Gene Mutation Database) ((

) Including all known (published) genetic lesions that cause human genetic diseases.

SzGene: the on-line database is called Schizophragene, a study related to schizophrenia heredity.

SZDB: the full name of the a database for schizophrenic Genetic Research, the Schizophrenia database (szdb), is a comprehensive resource for the study of Schizophrenia, integrating data related to Schizophrenia: genetic data (snp association from pgc2, snps and genes of genomic significance, genes affected by cnvs, genes fused functional genomics (cfg), genes analyzed by charlock ensemble, through association and linkage studies), gene expression data (spatio-temporal expression patterns and differentially expressed genes), network-based data (ppi and co-expression), brain eqtl data, coded data, and snp functional annotation information.

SZGR: it is called Schizophrenia gene resource, Schizophrenia gene bank.

PheGenI: phosphotype-genomic Integrator, which merges NHGRI genome-wide association study (GWAS) catalog data with several databases of the National Center for Biotechnology Information (NCBI), including Gene, dbGaP, OMIM, eQTL and dbSNP.

SNPedia: web site https:// www.snpedia.com/index.

Literature：Schizophrenia Working Group of the Psychiatric Genomics,C.Biological insights from 108schizophrenia-associated genetic loci.Nature511,421-427,doi:10.1038/nature13595(2014).