| Oxygen is an important component of the metabolism in animal,while its normal supply is essential to maintain the growth and development of animal,as well as the normal physiological functions of tissues and organs.The hypoxic environment often leads to insufficient oxygen supply of animal,which in turn produces a series of response about pathophysiology in animal.Most terrestrial mammals are less tolerant to hypoxia.However,due to long-term adaptation to the hypoxic environment of underground,subterranean rodents have developed a series of hypoxic adaptation strategies in different aspects,such as,behavior,physiology,and genetics.Lasiopodomys mandarinus is a typical subterranean rodent,while L.brandtii is a ground rodent.The two voles can be used as a good model for cross-species transcriptome analysis.L.mandarinus and L.brandtii were used as the research objects in this study.The treatment and control group of L.mandarinus and L.brandtii contained three adult male individuals,respectively.The treatment group were treated with 10% hypoxia in the laboratory hypoxia chamber for 48 hours.Then,the brain tissues were taken for transcriptome sequencing.After quality control,splicing,and annotation,cross-species transcriptome analysis was used to analyze the differential expression of cross-species under normoxia and intra-species under chronic hypoxia.The aim is to use the crossspecies transcriptome method to reveal the hypoxic adaptation mechanism in L.mandarinus,and to explore the direct comparison method of transcriptome between species,in order to provide a new technical direction for the study of the hypoxia adaptation of the subterranean rodent.The main findings are as follows:1)Each of L.mandarinus and L.brandtii had transcriptome sequencing data in brains of 6 samples.After quality control,a total of 89.4G bp clean data was obtained.The percentages of Q20 and Q30 were greater than or equal to 98.23% and87.26%,respectively.By the assembly of Trinity software,L.mandarinus obtained 75600 unigenes with a N50 of 2430 bp,while L.brandtii obtained 78281 unigenes with a N50 of 2506 bp.2)Using the databases of Nr,Swiss-prot,KEGG,and GO for function annotation of unigenes,L.mandarinus obtained 26013 annotation results,and L.brandtii obtained 25882 annotation results.A total of 12451 orthologous sequences of L.mandarinus and L.brandtii were obtained by Inparanoid for cross-species transcriptome analysis.3)By the different expression analysis of cross-species brain transcriptome under normoxia,with p.adj<0.05 and |log2foldchange|?1 as the standard,a total of 447 differentially expressed genes(DEGs)between L.mandarinus and L.brandtii were obtained,among which the high-expressed genes in L.mandarinus compared to L.brandtii were 219,and low-expressed genes were 228.The enrichment of GO found that genes activated ?-opioid receptor(DOR)to mediate cerebral ischemia / hypoxia tolerance,related to metabolism such as small molecule metabolism regulation,hormone secretion and regulation,and related to exercise such as feeding and nerve excitability were high-expressed in L.mandarinus;Genes related to hematopoiesis,angiogenesis regulation,and neurogenesis were low-expressed in L.mandarinus.The enrichment analysis results of KEGG pathwaywere similar to GO enriched results which were also supported by the analysis of protein interaction network.Those results suggested that L.mandarinus has good oxygen perception and regulation ability:(1)The m RNA transcribed from the HIF gene in cells under normoxic conditions will be degraded by oxygen,and the downstream genes regulated by it will be suppressed,showing low expression levels,especially genes related to hematopoiesis and neurogenesis;(2)Highly expressed genes are mainly involved in the functional regulation of brain tissue,and rarely involve structural changes.4)After removing the DEGs under normoxia between L.mandarinus and L.brandtii,the comparative transcriptome method was used to analyze the differential expression of intra-species hypoxic brain transcriptome.Under the condition of 10% oxygen,using p.adj<0.05 and |log2foldchange|?1 as the standard,136 and 103 DEGs of L.mandarinus and L.brandtii were obtained respectively.The GO enrichment analysis found that under 10% hypoxic conditions,(1)Genes related to cells and organisms hypoxia response were up-regulated in L.mandarinus such as angiogenesis,intracellular calcium / phosphate homeostasis regulation,cell migration;Genes related to myelination,neurofilament components,and the assembly and regulation of microtubule were down-regulated in L.mandarinus.(2)Genes such as the regulation of angiogenesis,blood coagulation,and red blood cell homeostasis were up-regulated in L.brandtii;Genes related to homeostasis regulation,such as carbohydrate and cationic homeostasis,and related to hormone secretion and transport were downregulated in L.brandtii;Genes related to exercise regulation,such as feeding behavior,dopamine biosynthesis were down-regulated in L.brandtii.The KEGG pathway enrichment analysis results were similar to GO enriched results,and protein interaction network analysis also supported GO enriched results.q PCR verified that the results of transcriptome analysis were reliable.Those results suggested that under the environment of 10% oxygen,L.mandarinus and L.brandtii have good hypoxic adaptability.L.mandarinus has reduced neuroprotection,while L.brandtii has intracellular homeostasis and exercise regulation Lowered.Conclusion: L.mandarinus has good oxygen sensing and regulation ability.Both vole use the cardiovascular system to deal with hypoxia,at the moment L.mandarinus has reduced neuroprotection,while L.brandtii has reduced intracellular homeostasis and motor regulation. |
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