Global identification of genes specific for rice meiosis
Ontology highlight
ABSTRACT: The leptotene-zygotene transition is a major step in meiotic progression during which pairing between homologous chromosomes is initiated and double strand breaks occur. OsAM1, a homolog of maize AM1 and Arabidopsis SWI1, encodes a protein with a coiled-coil domain in its central region that is required for the leptotene-zygotene transition during rice meiosis. To gain more insight into the role of OsAM1 in rice meiosis and to identify additional meiosis-specific genes, we characterized the transcriptomes of young panicles of Osam1 mutant and wild-type rice plants using RNA-Seq, bioinformatic and statistical analyses. As a result, a total of 25,750 and 28,455 genes were expressed in young panicles of wild-type and Osam1 mutant plants, respectively, and 4,400 differentially expressed genes (DEGs; log2 Ratio ≥ 1, FDR ≤ 0.05) were identified. Of these DEGs, four known rice meiosis-specific genes were detected, and 22 new putative meiosis-related genes were found by mapping these DEGs to reference biological pathways in the KEGG database. We identified eight additional well-conserved OsAM1-responsive rice meiotic genes by comparing our RNA-Seq data with known meiotic genes in Arabidopsis and fission yeast. We sequenced the transcriptome of young panicles of Osam1 mutant and wild-type rice.
Project description:The leptotene-zygotene transition is a major step in meiotic progression during which pairing between homologous chromosomes is initiated and double strand breaks occur. OsAM1, a homolog of maize AM1 and Arabidopsis SWI1, encodes a protein with a coiled-coil domain in its central region that is required for the leptotene-zygotene transition during rice meiosis. To gain more insight into the role of OsAM1 in rice meiosis and to identify additional meiosis-specific genes, we characterized the transcriptomes of young panicles of Osam1 mutant and wild-type rice plants using RNA-Seq, bioinformatic and statistical analyses. As a result, a total of 25,750 and 28,455 genes were expressed in young panicles of wild-type and Osam1 mutant plants, respectively, and 4,400 differentially expressed genes (DEGs; log2 Ratio ≥ 1, FDR ≤ 0.05) were identified. Of these DEGs, four known rice meiosis-specific genes were detected, and 22 new putative meiosis-related genes were found by mapping these DEGs to reference biological pathways in the KEGG database. We identified eight additional well-conserved OsAM1-responsive rice meiotic genes by comparing our RNA-Seq data with known meiotic genes in Arabidopsis and fission yeast.
Project description:Transfer of genetic traits from wild or related species into cultivated rice is nowadays an important aim in rice breeding. Breeders use genetic crosses to introduce desirable genes from exotic germplasms into cultivated rice varieties. However, in many hybrids there is only a low level of pairing (if existing) and recombination at early meiosis between cultivated rice and wild relative chromosomes. With the objective of getting deeper into the knowledge of the proteins involved in early meiosis, when chromosomes associate correctly in pairs and recombine, the proteome of isolated rice meiocytes has been characterized by nLC-MS/MS at every stage of early meiosis (prophase I). Up to 1316 different proteins have been identified in rice isolated meiocytes in early meiosis, being 422 exclusively identified in early prophase I (leptotene, zygotene or pachytene). The classification of proteins in functional groups showed that 167 were related to chromatin structure and remodelling, nucleic acid binding, cell-cycle regulation and cytoskeleton. Moreover, the putative roles of sixteen proteins which have not been previously associated to meiosis or were not identified in rice before, are also discussed namely: seven proteins involved in chromosome structure and remodeling, five regulatory proteins (such as SKP1 (OSK), a putative CDK2 like efector), a protein with RNA recognition motifs, a neddylation-related protein, and two microtubule-related proteins. Revealing the proteins involved in early meiotic processes could provide a valuable tool kit to manipulate chromosome associations during meiosis in rice breeding programs.
Project description:Meiotic recombination is initiated by the Spo11 endonuclease, which directs DNA double strand breaks at discrete regions in the genome coined hotspots. Here we report the profiles and dynamics of histone modifications at the cores of mouse recombination hotspots in early meiotic prophase. To define the spectrum of possible regulators of histone methylation and acetylation at all stages of meiosis I, expression analyses of histone acetylases/deacetylases (HATs/HDACs) and and HMTs/HDMTs genes when comparing those expressed in spermatogonia, pre-leptotene and leptotene/zygotene versus pachytene meiotic stages.
Project description:Prophase I of male meiosis involves dynamic chromosome segregation processes during early spermatogenesis, including synapsis, meiotic recombination, and cohesion. Genetic defects in genes participating in these processes consistently cause reproduction failure in mice. To identify candidate genes responsible for infertility in humans, we performed expression profiling of mouse spermatogenic cells undergoing meiotic prophase I. Cell fractions enriched in spermatogonia, leptotene/zygotene spermatocytes, or pachytene spermatocytes were separately isolated from mouse testes for RNA extraction. To minimize the contamination of other cell types, we fractionated the testicular cells undergoing the first round of spermatogenesis using Percoll gradient procedure. The cell fractions were characterized by morphological analysis by phase contrast microscopy and Nomarski interference microscopy, and then expression of cell lineage- and spermatogenesis stage-specific genes were examined by RT-PCR. The most enriched fractions for spermatogonia (fraction2 from day8), leptotene/zygotene spermatocytes (fraction5 from day12), and pachytene spermatocytes (fraction8 from day15) were subjected to hybridization on Affymetrix microarrays.
Project description:We combine synchronization of spermatogenesis, cytological analyses and single-cell RNA-seq (scRNA-seq) in the Sertoli cell androgen receptor knockout (SCARKO) mutant and control mice, and demonstrate that SCARKO mutant spermatocytes exhibited normal expression and localization of key protein markers of meiotic prophase events, indicating that initiation of meiotic prophase is not androgen dependent, whereas scRNA-seq analysis revealed a molecular transcriptomic block in an early meiotic prophase state (leptotene/zygotene) in mutant germ cells, and identified several misregulated genes in SCARKO Sertoli cells, many of which have been previously implicated in male infertility.
Project description:To describe the changes of transcriptome in Bend2 knockout mice, we conducted RNA-seq analyses by using leptotene and zygotene spermatocytes from Bend2 WT and KO mice. We found BEND2 contributes to shutting down the mitotic program and to activating or enhancing the meiotic and post-meiotic program of spermatogenic cells.
Project description:CXXC finger protein 1 (Cfp1) is a DNA-binding component of the SETD1 methyltransferase complex, targets SETD1A/B to most CpG islands (CpGI), and mediates the generation of H3K4me3. Deficiency of CFP1 in mice leads to pre-implantation lethality. Previous data suggest an indispensable role of CFP1 in germ cell development and meiosis. However, it remains unclear if CFP1-mediated H3K4 trimethylation is also required for the earliest stages of meiosis in both male and female germ cells. Here, we revealed that Cxxc1 deletion caused a decrease of H3K4me3 levels in spermatocytes after the zygotene stage, impaired double strand breaks (DSBs) repairing, and crossover formation in meiotic prophase. As the results, Cxxc1-deleted spermatocytes failed to complete meiosis and were arrested at the meiosis II. ChIP-seq results revealed that H3K4me3 globally descreased at transcriptional start sites in Cxxc1-null spermatocytes at the leptotene/zygotene and pathytene stages.RNA-seq at different stages revealed an earlier expression of genes within the spermatogenesis pathway in Cxxc1-null spermatocytes. These results indicated that CFP1 is required for H3K4me3 accumulation at the gene promoters of male germ cells and play a key role in regulating programed gene expression that is essential for spermatogenesis.
Project description:To better understand the mechanisms that regulate the heat stress response in rice, we conducted a comparative analysis of transcriptome profile in panicles from two rice lines, heat-tolerant line 252 (HTL252) and heat-susceptible line 082 (HSL082) using rice Affymetrix GeneChip. In HTL252 panicles, 1538 differentially expressed genes (DEGs) genes with at least four-fold expression changes compared with the control under heat treatment were considered heat-responsive (HR). Of these DEGs, 522 genes were up-regulated while 1016 genes were repressed. Among DEGs in HSL082, 496 genes were induced and 1707 genes were repressed. Out of the 370 common DEGs found between HTL252 and HSL082, 129 genes were induced and 241 genes were repressed.
Project description:R-loop is a three-strand nucleic acid structure composed of mRNA and DNA. In mammalian meiotic cells, R-loop mainly distributed at promoter-related regions, and combined with systematically transcriptome analysis showed R-loop was closely related to transcription in meiotic process. Moreover, knockout of Rnaseh1 in meiotic cells caused mice completely sterile with R-loop accumulation and abnormal DSB repairing in spermatocytes. Further analysis showed R-loop accumulation in leptotene/zygotene influenced transcriptional regulation in pachytene stage. Thus, mutual regulation of R-loop and transcription plays essential role in spermatogenesis.
Project description:Leaves and panicles from recurrent parent KMR3 and a high yielding KMR3-O.rufipogon introgression line were used Microarray analysis was carried out to reveal up- and down-regulated DEGs in leaves and panicles of control and experimental line for identifying key genes that help improve yield Leaves and fully emerged young panicles from both lines were used for RNA extraction and hybridization on Affymetrix microarrays