Analysis Of Growth And Development Of Pituitary Tissue In Southern China

In order to explore key functional genes related to growth and development of southern cattle and find out their regulatory mechanism,we analyzed the body weight, size and the growth-related hormone levels in plasma of Simmental, Yunling, and Wenshan cattle in Yunnan province. Then, RNA-seq and bioinformatics analysis were used to screen the differentially expressed genes in pituitary tissues of the three breeds. Finally, Q-PCR technology was used to verify the key genes.Simmental, Yunling, and Wenshan catties were housed under the same conditions and given the same diet (the forage-to-concentrate ratio was 65%:35%, and the daily intake was the 2.2% of body weight). Five bulls per breed were chosen at approximately 12 months of age, and they were fattened in 6 months. The body weight, size and the growth-related hormone levels in plasma were measured during the fattening period. The fattened cattles were weaned and their pituitary tissues were immediately collected which used for further RNA-seq and Q-PCR analysis.The main results are as follows:1.After determination in fattening period, we found that the weight of Simmental was the largest, and that of Wenshan was the smallest which was significantly smaller than that of Simmental and Yunling in each fattening month (P<0.01). After fattening, the stature, body length, heart girth, circumference of cannon bone of Wenshan were significantly smaller than that of Simmental and Yunling (P<0.05). The levels of the IGF-1, INS, GH, T4, T3 and TSH in plasma of Wenshan were significantly lower than Yunling cattle (P<0.05), of which the IGF-1, GH and T3 were also significantly lower than Simmental(P<0.05)2. Using RNA-seq to analysis the pituitary tissue of these southern cattles.The Simmental cattle as a control group, RNA-seq analysis screened out 1733 significantly differentially expressed genes of WenShan cattle, of which 944 genes were downregulated and 789 upregulated, and these genes were annotated to 3779 GO terms, RNA-seq analysis screened out 1275 significantly differentially expressed genes of Yunling cattle, of which 521 genes were upregulated and 754 downregulated, and these genes were annotated to 3214 GO terms (FC>2, P<0.05). The Yunling cattle as a control group, RNA-seq analysis screened out 1789 significantly differentially expressed genes of WenShan cattle, of which 817 genes were downregulated and 972 upregulated, and these genes were annotated to 4129 GO terms.3. Pathway analysis of these differentially expressed genes screened out a total of 25 significant Pathway:Hippo signaling pathway, PI3K-Akt signaling pathway, MAPK signaling pathway, Cytokine-cytokine receptor interaction, Rapl signaling pathway, Ras signaling pathway, Protein processing in endoplasmic reticulum, Neurotrophin signaling pathway, Cell cycle, Foxo signaling pathway, Signaling pathways regulating pluripotency of stem cells,etc.These Changes in pathways may be closely associated with the growth and development of the southern cattle. For example, the TRH gene enriched in Neuroactive ligand-receptor interaction pathway, it was downregulated state in Wenshan cattle’s pituitary tissue;In contrast, the TRH gene was upregulated state in Simmental and Yunling cattle’s pituitary tissue. This may stimulate the thyrotropin releasing hormone expression in Simmental and Yunling cattle, then promote the growth and development of simmental and yuengling cattle. Another example,the SSTR5 gene enriched in Neuroactive ligand-receptor interaction pathway,it was upregulated state in Wenshan cattle’s pituitary tissue. In contrast, the SSTR5 gene was downregulated state in Simmental and Yunling cattle’s pituitary tissue. This may stimulate the Somatostatin receptor expression in WenShan cattle, then promoted the effection of the Somatostatin and inhibited the effection of growth hormone and thyroid-stimulating hormones, resulting in the smaller size and slowly growth of WenShan cattle at last.4. Gene network planning analysis of these differentially expressed genes screened out a total of 35 hub genes:BMPR1B, TGFB2, BDNF, FIGF, CCNB1, CNTFR, CDKN2B, SSTR2, NGFR, PDGFC, JAG2, TNFRSF11B, PRLR, MAPK12, SSTR5, CDK6, FGF20, GAS1, GHRHR, TSHR, CKB and BMP6, etc.5. Part of significantly differentially expressed genes randomly selected, e.g. GHRHR、 JAG1、LRG1、FAM92B、LOC404103、CRYM、BDNF and SLC2A4 were verified using Q-PCR method.The results exposed the consistency between Q-PCR analysis and statistical analysis of transcriptomics data of differentially expressed genes.This study found that the hormone levels of IGF、GH、T3、T4、TSH and the differentially expressed genes(TTR、TSHR、TRH、SSTR5、SSTR2、IGFBP4、IGFBP5、GH)were closely related to growth and development of the southern cattle.These results and the genes(REC8、 BDNF、BMPR1B、MAP2K7、NGFR、TGFB2、BMP7、CDC20、FGF1) significantly enriched in KEGG terms of the growth and development of southern cattle were the candidate genes related to growth and development of southern cattle.