scholarly journals A co-expression network in hexaploid wheat reveals mostly balanced expression and lack of significant gene loss of homeologous meiotic genes upon polyploidization

2019 ◽  
Author(s):  
Abdul Kader Alabdullah ◽  
Philippa Borrill ◽  
Azahara C. Martin ◽  
Ricardo H. Ramirez-Gonzalez ◽  
Keywan Hassani-Pak ◽  
...  

AbstractPolyploidization has played an important role in plant evolution. However, upon polyploidization the process of meiosis must adapt to ensure the proper segregation of increased numbers of chromosomes to produce balanced gametes. It has been suggested that meiotic gene (MG) duplicates return to a single copy following whole genome duplication to stabilise the polyploid genome. Therefore, upon the polyploidization of wheat, a hexaploid species with three related (homeologous) genomes, the stabilization process may have involved rapid changes in content and expression of MGs on homeologous chromosomes (homeologs). To examine this hypothesis, sets of candidate MGs were identified in wheat using co-expression network analysis and orthology informed approaches. In total, 130 RNA-Seq samples from a range of tissues including wheat meiotic anthers were used to define co-expressed modules of genes. Three modules were significantly correlated with meiotic tissue samples but not with other tissue types. These modules were enriched for GO terms related to cell cycle, DNA replication and chromatin modification, and contained orthologs of known MGs. Overall 74.4 % of genes within these meiosis-related modules had three homeologous copies which was similar to other tissue-related modules. Amongst wheat MGs identified by orthology, rather than co-expression, the majority (93.7 %) were either retained in hexaploid wheat at the same number of copies (78.4 %) or increased in copy number (15.3%) compared to ancestral wheat species. Furthermore, genes within meiosis-related modules showed more balanced expression levels between homeologs than genes in non-meiosis-related modules. Taken together our results do not support extensive gene loss nor changes in homeolog expression of MGs upon wheat polyploidization. The construction of the MG co-expression network allowed identification of hub genes and provided key targets for future studies.Author summaryAll flowering plants have undergone a polyploidization event(s) during their evolutionary history. One of the biggest challenges faced by a newly-formed polyploid is meiosis, an essential event for sexual reproduction and fertility. This process must adapt to discriminate between multiple related chromosomes and to ensure their proper segregation to produce fertile gametes. The meiotic mechanisms responsible for the stabilisation of the extant polyploids remain poorly understood except in wheat, where there is now a better understanding of these processes. It has been proposed that meiotic adaptation in established polyploids could involve meiotic gene loss following the event of polyploidization. To test this hypothesis in hexaploid wheat, we have computationally predicted sets of hexaploid wheat meiotic genes based on expression data from different tissue types, including meiotic anther tissue, and orthology informed approaches. We have calculated homeolog expression patterns and number of gene copies for the predicted meiotic genes and compared them with proper control gene sets. Our findings did not support any significant meiotic gene loss upon wheat polyploidization. Furthermore, wheat meiotic genes showed more balanced expression levels between homeologs than non-meiotic genes.

2018 ◽  
Author(s):  
Alyssa N. Kruger ◽  
Quinn Ellison ◽  
Michele A. Brogley ◽  
Emma R. Gerlinger ◽  
Jacob L. Mueller

AbstractLarge (>10 kb) palindromic sequences are enriched on mammalian sex chromosomes. In mice, these palindromes harbor gene families (≥2 gene copies) expressed exclusively in post-meiotic testicular germ cells, at a time when most single-copy sex-linked genes are transcriptionally repressed. This distinct expression pattern led to the hypothesis that containment within palindrome structures or having ≥2 gene enables post-meiotic gene expression. We tested these two hypotheses by using CRISPR to precisely engineer large (10’s of kb) inversions and deletions of X chromosome palindrome arms for two regions carrying the mouse 4930567H17Rik and Mageb5 gene families. We found that 4930567H17Rik and Mageb5 gene expression is unaffected in mice carrying palindrome arm inversions, suggesting that palindromic structure is not important for mediating palindrome-associated gene expression. We also found that 4930567H17Rik and Mageb5 gene expression is reduced by half in mice carrying palindrome arm deletions, allowing us to test whether palindrome-associated genes are sensitive to reduced expression levels resulting in spermatogenic defects. Male mice carrying palindrome arm deletions of 4930567H17Rik or Mageb5, however, are fertile, have normal testis histology, and show no aberrations in spermatogenic cell population frequencies via FACS quantification. Together, these findings suggest that large palindromic structures on the sex chromosomes are not necessary for their associated genes to evade post-meiotic transcriptional repression and that these genes are not sensitive to reduced expression levels. Large sex chromosome palindromes may thus be important for other reasons, such as the long-term evolutionary stability of their associated gene families.


2020 ◽  
Vol 48 (12) ◽  
pp. 030006052093011
Author(s):  
Peng Jiang ◽  
Ming Zhang ◽  
Liangliang Gui ◽  
Kai Zhang

Objective Pancreatic adenocarcinoma (PAAD) is one of the most lethal malignant tumors worldwide. Various studies based on cell lines, preclinical mouse models, and human tissue samples have shown that cell cycle-associated proteins are involved in the tumorigenesis and progression of PAAD. Methods Herein, we analyzed the relationships between CDK1 and CCNA2 gene expression and prognosis in patients with pancreatic cancer, using information from the Oncomine, cBioportal, Kaplan–Meier Plotter, and GEPIA databases. Results Expression levels of CDK1 and CCNA2 were significantly higher in PAAD compared with control tissues, and were associated with more advanced tumor stage. Survival analyses using the Kaplan–Meier Plotter database further confirmed that increased expression levels of CDK1 and CCNA2 were associated with a poor prognosis in patients with pancreatic cancer. Conclusions The results of this study suggest that CDK1 and CCNA2 may be potential therapeutic targets and prognostic biomarkers in patients with PAAD.


2019 ◽  
Vol 64 (No. 2) ◽  
pp. 49-58
Author(s):  
L. Zhang ◽  
F. Peng ◽  
F. Yu ◽  
L. Wan ◽  
Z.-Q. Zhou

Supernumerary teats are commonly found in sheep. To investigate the expression levels of hormone receptors in supernumerary teats of Hu sheep, mammary tissue samples were collected from two groups of Hu sheep, four- and two-teat sheep, during adolescent (A), pregnancy (P), lactation (L), and non-pregnancy (N). Using hematoxylin and eosin staining, we found that mammary alveoli were denser in the four-teat sheep than in the two-teat sheep during P and L. Immunohistochemistry and Western blotting were used to detect the expression patterns and relative protein expression levels of the estrogen receptor 1 (ESR1), prolactin receptor (PRLR), growth hormone receptor (GHR), and insulin-like growth factor 1 receptor (IGF1R) in Hu sheep mammary glands during the four periods. All four receptors were mainly expressed in mammary epithelial cells and adipose cells. Furthermore, the expression levels of PRLR and GHR in the four-teat sheep were significantly higher than those in the two-teat sheep during P and L. Our data suggest that four-teat sheep have more developed mammary gland tissue compared with two-teat sheep.


Author(s):  
Behnaz Yazdani ◽  
Hajar Sirous

Background: Hypoxia-inducible factors (HIFs) are transcription factors that get activated and stabilized in the heterodimerized form under hypoxic conditions. The three members of the HIF alpha factors share high structural similarity but have tissue-specific expression patterns. A majority of studies have reported the importance of the HIF1A and HIF2A activity in the survival, proliferation, metastatic potential, and metabolic regulation of hypoxic cancer cells. However, the importance of the expression pattern and activity of HIF3A in a variety of cancers remains unknown. Method and materials: The expression profile of 13 different types of The Cancer Genome Atlas (TCGA) cancer samples were downloaded, normalized and differential gene expression analysis (DGE) was performed to compare the expression pattern of HIF alpha family members in cancer and adjacent normal tissues, as well as at different stages and tumor-sizes. Receiver operating characteristic (ROC) test and survival analysis were carried out to estimate the diagnostic potential of HIF alpha isomers in different cancers, as well as the survival rate of patients with the varying expression levels of HIF alpha factors. Results: The expression status of HIF3A was notably less in all cancer samples in contrast to their adjacent normal tissues. The expression degree of HIF1A varied among distinct types of cancer and the expression degree of HIF2A was lower in nearly all types of cancers. The expression level of HIF alpha isomers did not significantly correlate with different sizes of tumor samples and stages of different tumor tissue samples. HIF3A had very weak diagnostic potential, while HIF2A had better diagnostic potential in most types of cancers compared to HIF1A. Patients who had a higher level of HIF3A had better survival, while the higher expression levels of HIF1A and HIF2A were associated with worse survival in many types of cancers. Conclusion: Our study shows the heterogenous expression pattern of HIF alpha subunits in distinctive kinds of cancers and the influence of HIF3A expression level in the survival of patients with varying types of cancers.


2021 ◽  
Vol 49 (1) ◽  
pp. 030006052098154
Author(s):  
Xin Yuan ◽  
Yize Zhang ◽  
Zujiang Yu

Objective To investigate the association between microRNA-3615 (miR-3615) expression and the prognosis and clinicopathological features in patients with hepatocellular carcinoma (HCC). Methods We obtained clinicopathological and genomic data and prognostic information on HCC patients from The Cancer Genome Atlas (TCGA) database. We then analyzed differences in miR-3615 expression levels between HCC and adjacent tissues using SPSS software, and examined the relationships between miR-3615 expression levels and clinicopathological characteristics. We also explored the influence of miR-3615 expression levels on the prognosis of HCC patients using Kaplan–Meier survival curve analysis. Results Based on data for 345 HCC and 50 adjacent normal tissue samples, expression levels of miR-3615 were significantly higher in HCC tissues compared with adjacent tissues. MiR-3615 expression levels in HCC patients were negatively correlated with overall survival time and positively correlated with high TNM stage, serum Ki-67 expression level, and serum alpha-fetoprotein level. There were no significant correlations between miR-3615 expression and age, sex, and pathological grade. Conclusion MiR-3615 may be a promising new biomarker and prognostic factor for HCC.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tao Fan ◽  
Yu-Zhen Zhao ◽  
Jing-Fang Yang ◽  
Qin-Lai Liu ◽  
Yuan Tian ◽  
...  

AbstractEukaryotic cells can expand their coding ability by using their splicing machinery, spliceosome, to process precursor mRNA (pre-mRNA) into mature messenger RNA. The mega-macromolecular spliceosome contains multiple subcomplexes, referred to as small nuclear ribonucleoproteins (snRNPs). Among these, U1 snRNP and its central component, U1-70K, are crucial for splice site recognition during early spliceosome assembly. The human U1-70K has been linked to several types of human autoimmune and neurodegenerative diseases. However, its phylogenetic relationship has been seldom reported. To this end, we carried out a systemic analysis of 95 animal U1-70K genes and compare these proteins to their yeast and plant counterparts. Analysis of their gene and protein structures, expression patterns and splicing conservation suggest that animal U1-70Ks are conserved in their molecular function, and may play essential role in cancers and juvenile development. In particular, animal U1-70Ks display unique characteristics of single copy number and a splicing isoform with truncated C-terminal, suggesting the specific role of these U1-70Ks in animal kingdom. In summary, our results provide phylogenetic overview of U1-70K gene family in vertebrates. In silico analyses conducted in this work will act as a reference for future functional studies of this crucial U1 splicing factor in animal kingdom.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ruifeng Cui ◽  
Xiaoge Wang ◽  
Waqar Afzal Malik ◽  
Xuke Lu ◽  
Xiugui Chen ◽  
...  

Abstract Background The Raffinose synthetase (RAFS) genes superfamily is critical for the synthesis of raffinose, which accumulates in plant leaves under abiotic stress. However, it remains unclear whether RAFS contributes to resistance to abiotic stress in plants, specifically in the Gossypium species. Results In this study, we identified 74 RAFS genes from G. hirsutum, G. barbadense, G. arboreum and G. raimondii by using a series of bioinformatic methods. Phylogenetic analysis showed that the RAFS gene family in the four Gossypium species could be divided into four major clades; the relatively uniform distribution of the gene number in each species ranged from 12 to 25 based on species ploidy, most likely resulting from an ancient whole-genome polyploidization. Gene motif analysis showed that the RAFS gene structure was relatively conservative. Promoter analysis for cis-regulatory elements showed that some RAFS genes might be regulated by gibberellins and abscisic acid, which might influence their expression levels. Moreover, we further examined the functions of RAFS under cold, heat, salt and drought stress conditions, based on the expression profile and co-expression network of RAFS genes in Gossypium species. Transcriptome analysis suggested that RAFS genes in clade III are highly expressed in organs such as seed, root, cotyledon, ovule and fiber, and under abiotic stress in particular, indicating the involvement of genes belonging to clade III in resistance to abiotic stress. Gene co-expressed network analysis showed that GhRFS2A-GhRFS6A, GhRFS6D, GhRFS7D and GhRFS8A-GhRFS11A were key genes, with high expression levels under salt, drought, cold and heat stress. Conclusion The findings may provide insights into the evolutionary relationships and expression patterns of RAFS genes in Gossypium species and a theoretical basis for the identification of stress resistance materials in cotton.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Peirong Li ◽  
Tongbing Su ◽  
Deshuang Zhang ◽  
Weihong Wang ◽  
Xiaoyun Xin ◽  
...  

AbstractHeterosis is a complex phenomenon in which hybrids show better phenotypic characteristics than their parents do. Chinese cabbage (Brassica rapa L. spp. pekinensis) is a popular leafy crop species, hybrids of which are widely used in commercial production; however, the molecular basis of heterosis for biomass of Chinese cabbage is poorly understood. We characterized heterosis in a Chinese cabbage F1 hybrid cultivar and its parental lines from the seedling stage to the heading stage; marked heterosis of leaf weight and biomass yield were observed. Small RNA sequencing revealed 63 and 50 differentially expressed microRNAs (DEMs) at the seedling and early-heading stages, respectively. The expression levels of the majority of miRNA clusters in the F1 hybrid were lower than the mid-parent values (MPVs). Using degradome sequencing, we identified 1,819 miRNA target genes. Gene ontology (GO) analyses demonstrated that the target genes of the MPV-DEMs and low parental expression level dominance (ELD) miRNAs were significantly enriched in leaf morphogenesis, leaf development, and leaf shaping. Transcriptome analysis revealed that the expression levels of photosynthesis and chlorophyll synthesis-related MPV-DEGs (differentially expressed genes) were significantly different in the F1 hybrid compared to the parental lines, resulting in increased photosynthesis capacity and chlorophyll content in the former. Furthermore, expression of genes known to regulate leaf development was also observed at the seedling stage. Arabidopsis plants overexpressing BrGRF4.2 and bra-miR396 presented increased and decreased leaf sizes, respectively. These results provide new insight into the regulation of target genes and miRNA expression patterns in leaf size and heterosis for biomass of B. rapa.


Cancers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1480
Author(s):  
Hiresh Ayoubian ◽  
Joana Heinzelmann ◽  
Sebastian Hölters ◽  
Oybek Khalmurzaev ◽  
Alexey Pryalukhin ◽  
...  

Although microRNAs are described as promising biomarkers in many tumor types, little is known about their role in PSCC. Thus, we attempted to identify miRNAs involved in tumor development and metastasis in distinct histological subtypes considering the impact of HPV infection. In a first step, microarray analyses were performed on RNA from formalin-fixed, paraffin-embedded tumor (22), and normal (8) tissue samples. Microarray data were validated for selected miRNAs by qRT-PCR on an enlarged cohort, including 27 tumor and 18 normal tissues. We found 876 significantly differentially expressed miRNAs (p ≤ 0.01) between HPV-positive and HPV-negative tumor samples by microarray analysis. Although no significant differences were detected between normal and tumor tissue in the whole cohort, specific expression patterns occurred in distinct histological subtypes, such as HPV-negative usual PSCC (95 differentially expressed miRNAs, p ≤ 0.05) and HPV-positive basaloid/warty subtypes (247 differentially expressed miRNAs, p ≤ 0.05). Selected miRNAs were confirmed by qRT-PCR. Furthermore, microarray data revealed 118 miRNAs (p ≤ 0.01) that were significantly differentially expressed in metastatic versus non-metastatic usual PSCC. The lower expression levels for miR-137 and miR-328-3p in metastatic usual PSCC were validated by qRT-PCR. The results of this study confirmed that specific miRNAs could serve as potential diagnostic and prognostic markers in single PSCC subtypes and are associated with HPV-dependent pathways.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Guanying Gao ◽  
Ruiqi Wu ◽  
Rongge Liu ◽  
Jianquan Wang ◽  
Yingfang Ao ◽  
...  

Abstract Background Recent studies have shown high expression levels of certain inflammatory, anabolic, and catabolic genes in the articular cartilage from the impingement zone of the hips with femoroacetabular impingement (FAI), representing an increased metabolic state. Nevertheless, little is known about the molecular properties of bone tissue from the impingement zone of hips with FAI. Methods Bone tissue samples from patients with early-stage cam-type FAI were collected during hip arthroscopy for treatment of cam-type FAI. Control bone tissue samples were collected from six patients who underwent total hip replacement because of a femoral neck fracture. Quantitative real-time polymerase chain reaction (PCR) was performed to determine the gene expression associated with inflammation and bone remodeling. The differences in the gene expression in bone tissues from the patients with early-stage cam-type FAI were also evaluated based on clinical parameters. Results In all, 12 patients with early-stage cam-type FAI and six patients in the control group were included in this study. Compared to the control samples, the bone tissue samples from patients with FAI showed higher expression levels of interleukin-6 (IL-6), alkaline phosphatase (ALP), receptor activator of nuclear factor-kB ligand (RANKL), and osteoprotegerin (OPG) (P < 0.05). IL-1 expression was detected only in the control group. On the other hand, there was no significant difference in IL-8 expression between the patients with FAI and the control group. The patients with FAI having a body mass index (BMI) of >24 kg/m2 showed higher ALP expression (P < 0.05). Further, the expression of IL-6 and ALP was higher in the patients with FAI in whom the lateral center-edge angle was >30° (P < 0.05). Conclusions Our results indicated the metabolic condition of bone tissues in patients with early-stage cam-type FAI differed from that of normal bone in the femoral head-neck junction. The expression levels of the genes associated with inflammation and bone remodeling were higher in the bone tissue of patients with early-stage cam-type FAI than in the patients with normal bone tissue.


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