scholarly journals Dnmt3aa but Not Dnmt3ab Is Required for Maintenance of Gametogenesis in Nile Tilapia (Oreochromis niloticus)

2021 ◽  
Vol 22 (18) ◽  
pp. 10170
Author(s):  
Feilong Wang ◽  
Zuliang Qin ◽  
Zhiqiang Li ◽  
Shuangyi Yang ◽  
Tian Gao ◽  
...  

Dnmt3a, a de novo methyltransferase, is essential for mammalian germ line DNA methylation. Only one Dnmt3a is identified in mammals, and homozygous mutants of Dnmt3a are lethal, while two Dnmt3a paralogs, dnmt3aa and dnmt3ab, are identified in teleosts due to the third round of genome duplication, and homozygous mutants of dnmt3aa and dnmt3ab are viable in zebrafish. The expression patterns and roles of dnmt3aa and dnmt3ab in gonadal development remain poorly understood in teleosts. In this study, we elucidated the precise expression patterns of dnmt3aa and dnmt3ab in tilapia gonads. Dnmt3aa was highly expressed in oogonia, phase I and II oocytes and granulosa cells in ovaries and spermatogonia and spermatocytes in testes, while dnmt3ab was mainly expressed in ovarian granulosa cells and testicular spermatocytes. The mutation of dnmt3aa and dnmt3ab was achieved by CRISPR/Cas9 in tilapia. Lower gonadosomatic index (GSI), increased apoptosis of oocytes and spermatocytes and significantly reduced sperm quality were observed in dnmt3aa−/− mutants, while normal gonadal development was observed in dnmt3ab−/− mutants. Consistently, the expression of apoptotic genes was significantly increased in dnmt3aa−/− mutants. In addition, the 5-methylcytosine (5-mC) level in dnmt3aa−/− gonads was decreased significantly, compared with that of dnmt3ab−/− and wild type (WT) gonads. Taken together, our results suggest that dnmt3aa, not dnmt3ab, plays important roles in maintaining gametogenesis in teleosts.

2021 ◽  
Author(s):  
Feilong Wang ◽  
Zuliang Qin ◽  
Zhiqiang Li ◽  
Shuangyi Yang ◽  
Tian Gao ◽  
...  

Abstract Background: Dnmt3a , a de novo methylatransferase, is essential for both male and female germ line DNA methylation. Only one Dnmt3a is identified in mammals, and homozygous mutation of Dnmt3a is lethal, while two Dnmt3a , dnmt3aa and dnmt3ab , are identified in teleosts due to the third round of genome duplication, and homozygous mutation of dnmt3aa and dnmt3ab is viable in zebrafish. Dnmt3aa and dnmt3ab were demonstrated to have essential and non-overlapped functions on modulating behavioral control, however, their function in gonadal development is unclear in fish. Results: In this study, the expression patterns of dnmt3aa and dnmt3ab in developing gonads of Nile tilapia was analyzed by quantitative real time PCR and fluorescence in situ hybridization. Both dnmt3aa and dnmt3ab displayed sexually dimorphic expression in developing gonads. Dnmt3aa was widely expressed in gonadal germ cells and somatic cells, highly expressed in oogonia, phase I and II oocytes and granulosa cells in ovaries and spermatogonia and spermatocytes in testes, while dnmt3ab was mainly expressed in ovarian granulosa cells and testicular spermatocytes. Mutation of dnmt3aa and dnmt3ab was achieved by CRISPR/Cas9 in tilapia. Lower GSI (Gonadosomatic index), increased apoptosis of oocytes and spermatocytes and significantly reduced sperm quality were observed in dnmt3aa −/− mutants, while no obvious phenotype was observed in dnmt3ab −/− mutants. Consistently, the expression of apoptotic genes was significantly increased in dnmt3aa −/− mutants. In addition, dnmt3aa and dnmt3ab were found to have certain compensatory effects in the gonads. The global DNA methylation level in ovaries and testes of dnmt3aa −/− mutants was decreased significantly, compared with that of dnmt3ab −/− mutants and WT. Conclusions: Taken together, our results suggest that dnmt3aa , not dnmt3ab , plays important roles in maintaining gametogenesis in teleost. Our results enrich the understanding of the function of DNA methyltransferases in gonads of non-mammalian vertebrates.


BMC Genomics ◽  
2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Inés González-Castellano ◽  
Chiara Manfrin ◽  
Alberto Pallavicini ◽  
Andrés Martínez-Lage

Abstract Background The common littoral shrimp Palaemon serratus is an economically important decapod resource in some European communities. Aquaculture practices prevent the genetic deterioration of wild stocks caused by overfishing and at the same time enhance the production. The biotechnological manipulation of sex-related genes has the proved potential to improve the aquaculture production but the scarcity of genomic data about P. serratus hinders these applications. RNA-Seq analysis has been performed on ovary and testis samples to generate a reference gonadal transcriptome. Differential expression analyses were conducted between three ovary and three testis samples sequenced by Illumina HiSeq 4000 PE100 to reveal sex-related genes with sex-biased or sex-specific expression patterns. Results A total of 224.5 and 281.1 million paired-end reads were produced from ovary and testis samples, respectively. De novo assembly of ovary and testis trimmed reads yielded a transcriptome with 39,186 transcripts. The 29.57% of the transcriptome retrieved at least one annotation and 11,087 differentially expressed genes (DEGs) were detected between ovary and testis replicates. Six thousand two hundred seven genes were up-regulated in ovaries meanwhile 4880 genes were up-regulated in testes. Candidate genes to be involved in sexual development and gonadal development processes were retrieved from the transcriptome. These sex-related genes were discussed taking into account whether they were up-regulated in ovary, up-regulated in testis or not differentially expressed between gonads and in the framework of previous findings in other crustacean species. Conclusions This is the first transcriptome analysis of P. serratus gonads using RNA-Seq technology. Interesting findings about sex-related genes from an evolutionary perspective (such as Dmrt1) and for putative future aquaculture applications (Iag or vitellogenesis genes) are reported here. We provide a valuable dataset that will facilitate further research into the reproductive biology of this shrimp.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1465
Author(s):  
Ramon de Koning ◽  
Raphaël Kiekens ◽  
Mary Esther Muyoka Toili ◽  
Geert Angenon

Raffinose family oligosaccharides (RFO) play an important role in plants but are also considered to be antinutritional factors. A profound understanding of the galactinol and RFO biosynthetic gene families and the expression patterns of the individual genes is a prerequisite for the sustainable reduction of the RFO content in the seeds, without compromising normal plant development and functioning. In this paper, an overview of the annotation and genetic structure of all galactinol- and RFO biosynthesis genes is given for soybean and common bean. In common bean, three galactinol synthase genes, two raffinose synthase genes and one stachyose synthase gene were identified for the first time. To discover the expression patterns of these genes in different tissues, two expression atlases have been created through re-analysis of publicly available RNA-seq data. De novo expression analysis through an RNA-seq study during seed development of three varieties of common bean gave more insight into the expression patterns of these genes during the seed development. The results of the expression analysis suggest that different classes of galactinol- and RFO synthase genes have tissue-specific expression patterns in soybean and common bean. With the obtained knowledge, important galactinol- and RFO synthase genes that specifically play a key role in the accumulation of RFOs in the seeds are identified. These candidate genes may play a pivotal role in reducing the RFO content in the seeds of important legumes which could improve the nutritional quality of these beans and would solve the discomforts associated with their consumption.


Genes ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 663
Author(s):  
Stijn van de Plassche ◽  
Arjan PM de Brouwer

MED12 is a member of the Mediator complex that is involved in the regulation of transcription. Missense variants in MED12 cause FG syndrome, Lujan-Fryns syndrome, and Ohdo syndrome, as well as non-syndromic intellectual disability (ID) in hemizygous males. Recently, female patients with de novo missense variants and de novo protein truncating variants in MED12 were described, resulting in a clinical spectrum centered around ID and Hardikar syndrome without ID. The missense variants are found throughout MED12, whether they are inherited in hemizygous males or de novo in females. They can result in syndromic or nonsyndromic ID. The de novo nonsense variants resulting in Hardikar syndrome that is characterized by facial clefting, pigmentary retinopathy, biliary anomalies, and intestinal malrotation, are found more N-terminally, whereas the more C-terminally positioned variants are de novo protein truncating variants that cause a severe, syndromic phenotype consisting of ID, facial dysmorphism, short stature, skeletal abnormalities, feeding difficulties, and variable other abnormalities. This broad range of distinct phenotypes calls for a method to distinguish between pathogenic and non-pathogenic variants in MED12. We propose an isogenic iNeuron model to establish the unique gene expression patterns that are associated with the specific MED12 variants. The discovery of these patterns would help in future diagnostics and determine the causality of the MED12 variants.


2017 ◽  
Vol 2017 ◽  
pp. 1-18 ◽  
Author(s):  
Baoyun Zhang ◽  
Long Chen ◽  
Guangde Feng ◽  
Wei Xiang ◽  
Ke Zhang ◽  
...  

Ovaries, which provide a place for follicular development and oocyte maturation, are important organs in female mammals. Follicular development is complicated physiological progress mediated by various regulatory factors including microRNAs (miRNAs). To demonstrate the role of miRNAs in follicular development, this study analyzed the expression patterns of miRNAs in granulosa cells through investigating three previous datasets generated by Illumina miRNA deep sequencing. Furthermore, via bioinformatic analyses, we dissected the associated functional networks of the observed significant miRNAs, in terms of interacting with signal pathways and transcription factors. During the growth and selection of dominant follicles, 15 dysregulated miRNAs and 139 associated pathways were screened out. In comparison of different styles of follicles, 7 commonly abundant miRNAs and 195 pathways, as well as 10 differentially expressed miRNAs and 117 pathways in dominant follicles in comparison with subordinate follicles, were collected. Furthermore, SMAD2 was identified as a hub factor in regulating follicular development. The regulation of miR-26a/b onsmad2messenger RNA has been further testified by real time PCR. In conclusion, we established functional networks which play critical roles in follicular development including pivotal miRNAs, pathways, and transcription factors, which contributed to the further investigation about miRNAs associated with mammalian follicular development.


2002 ◽  
Vol 76 (15) ◽  
pp. 7578-7586 ◽  
Author(s):  
Bodil Øster ◽  
Per Höllsberg

ABSTRACT Herpesvirus gene expression is divided into immediate-early (IE) or α genes, early (E) or β genes, and late (L) or γ genes on the basis of temporal expression and dependency on other gene products. By using real-time PCR, we have investigated the expression of 35 human herpesvirus 6B (HHV-6B) genes in T cells infected by strain PL-1. Kinetic analysis and dependency on de novo protein synthesis and viral DNA polymerase activity suggest that the HHV-6B genes segregate into six separate kinetic groups. The genes expressed early (groups I and II) and late (groups V and VI) corresponded well with IE and L genes, whereas the intermediate groups III and IV contained E and L genes. Although HHV-6B has characteristics similar to those of other roseoloviruses in its overall gene regulation, we detected three B-variant-specific IE genes. Moreover, genes that were independent of de novo protein synthesis clustered in an area of the viral genome that has the lowest identity to the HHV-6A variant. The organization of IE genes in an area of the genome that differs from that of HHV-6A underscores the distinct differences between HHV-6B and HHV-6A and may provide a basis for further molecular and immunological analyses to elucidate their different biological behaviors.


2013 ◽  
Vol 94 (5) ◽  
pp. 960-970 ◽  
Author(s):  
Gernot Wolf ◽  
Anders Lade Nielsen ◽  
Jacob Giehm Mikkelsen ◽  
Finn Skou Pedersen

Endogenous retroviruses (ERVs) are remnants of retroviral germ line infections and have been identified in all mammals investigated so far. Although the majority of ERVs are degenerated, some mammalian species, such as mice and pigs, carry replication-competent ERVs capable of forming infectious viral particles. In mice, ERVs are silenced by DNA methylation and histone modifications and some exogenous retroviruses were shown to be transcriptionally repressed after integration by a primer-binding site (PBS) targeting mechanism. However, epigenetic repression of porcine ERVs (PERVs) has remained largely unexplored so far. In this study, we screened the pig genome for PERVs using LTRharvest, a tool for de novo detection of ERVs, and investigated various aspects of epigenetic repression of three unrelated PERV families. We found that these PERV families are differentially up- or downregulated upon chemical inhibition of DNA methylation and histone deacetylation in cultured porcine cells. Furthermore, chromatin immunoprecipitation analysis revealed repressive histone methylation marks at PERV loci in primary porcine embryonic germ cells and immortalized embryonic kidney cells. PERV elements belonging to the PERV-γ1 family, which is the only known PERV family that has remained active up to the present, were marked by significantly higher levels of histone methylations than PERV-γ2 and PERV-β3 proviruses. Finally, we tested three PERV-associated PBS sequences for repression activity in murine and porcine cells using retroviral transduction experiments and showed that none of these PBS sequences induced immediate transcriptional silencing in the tested primary porcine cells.


2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Liangbin Zeng ◽  
Airong Shen ◽  
Jia Chen ◽  
Zhun Yan ◽  
Touming Liu ◽  
...  

The ramie mothCocytodes coeruleaGuenée (RM) is an economically important pest that seriously impairs the yield of ramie, an important natural fiber crop. The molecular mechanisms that underlie the ramie-pest interactions are unclear up to date. Therefore, a transcriptome profiling analysis would aid in understanding the ramie defense mechanisms against RM. In this study, we first constructed two cDNA libraries derived from RM-challenged (CH) and unchallenged (CK) ramie leaves. The subsequent sequencing of the CH and CK libraries yielded 40.2 and 62.8 million reads, respectively. Furthermore,de novoassembling of these reads generated 26,759 and 29,988 unigenes, respectively. An integrated assembly of data from these two libraries resulted in 46,533 unigenes, with an average length of 845 bp per unigene. Among these genes, 24,327 (52.28%) were functionally annotated by predicted protein function. A comparative analysis of the CK and CH transcriptome profiles revealed 1,980 differentially expressed genes (DEGs), of which 750 were upregulated and 1,230 were downregulated. A quantitative real-time PCR (qRT-PCR) analysis of 13 random selected genes confirmed the gene expression patterns that were determined by Illumina sequencing. Among the DEGs, the expression patterns of transcription factors, protease inhibitors, and antioxidant enzymes were studied. Overall, these results provide useful insights into the defense mechanism of ramie against RM.


2021 ◽  
Vol 22 (23) ◽  
pp. 13005
Author(s):  
Tuo Zeng ◽  
Jia-Wen Li ◽  
Li Zhou ◽  
Zhi-Zhuo Xu ◽  
Jin-Jin Li ◽  
...  

Natural pyrethrins have been widely used as natural pesticides due to their low mammalian toxicity and environmental friendliness. Previous studies have mainly focused on Tanacetum cinerariifolium, which contains high levels of pyrethrins and volatile terpenes that play significant roles in plant defense and pollination. However, there is little information on T. coccineum due to its lower pyrethrin content and low commercial value. In this study, we measured the transcriptome and metabolites of the leaves (L), flower buds (S1), and fully blossomed flowers (S4) of T. coccineum. The results show that the expression of pyrethrins and precursor terpene backbone genes was low in the leaves, and then rapidly increased in the S1 stage before decreasing again in the S4 stage. The results also show that pyrethrins primarily accumulated at the S4 stage. However, the content of volatile terpenes was consistently low. This perhaps suggests that, despite T. coccineum and T. cinerariifolium having similar gene expression patterns and accumulation of pyrethrins, T. coccineum attracts pollinators via its large and colorful flowers rather than via inefficient and metabolically expensive volatile terpenes, as in T. cinerariifolium. This is the first instance of de novo transcriptome sequencing reported for T. coccineum. The present results could provide insights into pyrethrin biosynthetic pathways and will be helpful for further understanding how plants balance the cost–benefit relationship between plant defense and pollination.


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