De novo formation in maize from irradiated materials
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PROVIDER: PRJNA511397 | ENA |
REPOSITORIES: ENA
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Project description:In maize (Zea mays), irradiation can produce many variants with varying centromeric DNA sequences. We found de novo centromeres in F3-152 and F3-600, which has no canonical centromeric repeat sequences. This centromere is derived from a 1520-kb and 188-kb region on the arm of chromosome 10 and 3. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution.
2019-12-21 | GSE124242 | GEO
Project description:The ability of centromeres to alternate between active and inactive states indicates significant epigenetic elements controlling centromere assembly and centromere function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In derivatives of TB-9Sb, we found a de novo centromere on chromosome telo-3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. This centromere is much smaller than normal ones but can be maintained through meiosis. The functional B centromere in progenitor telo2-2 is deleted from telo3-3 but some B-repeat sequences remain. The de novo centromere of telo3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on the chromosomes. One such de novo centromere contains only 200-kb CENH3 binding domain. This 200-kb centromere is located 3 Mb removed from the translocation breakpoint in a new location. The deleted B centromere in telo3-3 is activated in two derivatives. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution. ChIP-seq was carried out with anti-CENH3 antibodies using material from young leaves with control, telo3-3 and its derivate.
2015-03-03 | E-GEOD-59124 | biostudies-arrayexpress
Project description:The ability of centromeres to alternate between active and inactive states indicates significant epigenetic elements controlling centromere assembly and centromere function. In maize (Zea mays), misdivision of the B chromosome centromere on a translocation with the short arm of chromosome 9 (TB-9Sb) can produce many variants with varying centromere sizes and centromeric DNA sequences. In derivatives of TB-9Sb, we found a de novo centromere on chromosome telo-3-3, which has no canonical centromeric repeat sequences. This centromere is derived from a 288-kb region on the short arm of chromosome 9, and is 19 megabases (Mb) removed from the translocation breakpoint of chromosome 9 in TB-9Sb. This centromere is much smaller than normal ones but can be maintained through meiosis. The functional B centromere in progenitor telo2-2 is deleted from telo3-3 but some B-repeat sequences remain. The de novo centromere of telo3-3 becomes inactive in three further derivatives with new centromeres being formed elsewhere on the chromosomes. One such de novo centromere contains only 200-kb CENH3 binding domain. This 200-kb centromere is located 3 Mb removed from the translocation breakpoint in a new location. The deleted B centromere in telo3-3 is activated in two derivatives. Our results suggest that de novo centromere formation is more common than previously thought and can persist on chromosomal fragments without a canonical centromere providing implications for karyotype evolution.
2015-03-03 | GSE59124 | GEO
Project description:We report de novo genome assemblies, transcriptomes, annotations, and methylomes for the 26 maize inbreds that serve as the founders for the maize nested association mapping population. The data indicate that the number of pan-genes in maize exceeds 103,000 and that the ancient tetraploid character of maize continues to degrade by fractionation to the present day. Excellent contiguity over repeat arrays and complete annotation of centromeres further revealed the locations and internal structures of major cytological landmarks. We show that combining structural variation with SNPs can improve the power of quantitative mapping studies. Finally, we document variation at the level of DNA methylation, and demonstrate that unmethylated regions are enriched for cis-regulatory elements that correlate with known QTLs and changes in gene expression.
2021-02-01 | GSE165787 | GEO
Project description:De novo centromeres originate occasionally from non-centromeric regions of chromosomes, providing an excellent model system to study centromeric chromatin. The maize mini-chromosome Dp3a contains a de novo centromere, which was derived from a euchromatic site on the long arm of chromosome 3 that lacks traditional centromeric repeat sequences. Our previous study found that the CENH3 binding domain of this de novo centromere is only 350 kb with a high-density gene distribution with low-density of transposons. Here we analyzed the kinetochore complex assembled on the de novo centromere, which revealed that it resembles the native centromeres. Meiotic analyses showed that the Dp3a mini-chromosome formed bi-orientation during meiosis I and could stably transmit through meiosis. We applied next generation sequencing technology to analyze gene transcription, DNA methylation and histone modifications for this region. Our RNA-seq data revealed that active chromatin is not a barrier for de novo centromere formation. The gene expression level within the Dp3a breakpoints of native chromosome 3 indicated a gene dosage effect due to the additional copy of Dp3a mini-chromosome region in chromosome 3. Bisulfite-ChIP-seq results indicate a slightly increased DNA methylation level after de novo centromere formation, reaching the level of a native centromere. No strand-specific bias of DNA methylation was found at maize native and Dp3a de novo centromeres. H2A-T133 phosphorylation occurs in the CENH3 nucleosome. These results provide insight into the mechanism of de novo centromere formation and subsequent consequences.
2016-12-01 | GSE64641 | GEO
Project description:De novo centromeres originate occasionally from non-centromeric regions of chromosomes, providing an excellent model system to study centromeric chromatin. The maize mini-chromosome Derivative 3-3 contains a de novo centromere, which was derived from a euchromatic site on the short arm of chromosome 9 that lacks traditional centromeric repeat sequences. Our previous study found that the CENH3 binding domain of this de novo centromere is only 288 kb with a high-density gene distribution with low-density of transposons. Here we applied next generation sequencing technology to analyze gene transcription, DNA methylation for this region. Our RNA-seq data revealed that active chromatin is not a barrier for de novo centromere formation. Bisulfite-ChIP-seq results indicate a slightly increased DNA methylation level after de novo centromere formation, reaching the level of a native centromere. These results provide insight into the mechanism of de novo centromere formation and subsequent consequences. RNA-seq was carried out using material from seedling and young leaves between control and Derivative 3-3. Bisulfite-ChIP-seq was carried out with anti-CENH3 antibodies using material from young leaves in Derivative 3-3.
2016-08-05 | E-GEOD-76533 | biostudies-arrayexpress
Project description:De novo centromeres originate occasionally from non-centromeric regions of chromosomes, providing an excellent model system to study centromeric chromatin. The maize mini-chromosome Derivative 3-3 contains a de novo centromere, which was derived from a euchromatic site on the short arm of chromosome 9 that lacks traditional centromeric repeat sequences. Our previous study found that the CENH3 binding domain of this de novo centromere is only 288 kb with a high-density gene distribution with low-density of transposons. Here we applied next generation sequencing technology to analyze gene transcription, DNA methylation for this region. Our RNA-seq data revealed that active chromatin is not a barrier for de novo centromere formation. Bisulfite-ChIP-seq results indicate a slightly increased DNA methylation level after de novo centromere formation, reaching the level of a native centromere. These results provide insight into the mechanism of de novo centromere formation and subsequent consequences.
2016-08-05 | GSE76533 | GEO
Project description:The centromere is the part of the chromosome that organizes the kinetochore, which mediates chromosome movement during mitosis and meiosis. A small fragment from chromosome 3, named Duplication 3a (Dp3a), was described from UV-irradiated materials by Stadler and Roman in the 1940s [Stadler LJ, Roman H (1948) Genetics 33(3):273-303]. The genetic behavior of Dp3a is reminiscent of a ring chromosome, but fluoresecent in situ hybridization detected telomeres at both ends, suggesting a linear structure. This small chromosome has no detectable canonical centromeric sequences, but contains a site with protein features of functional centromeres such as CENH3, the centromere specific H3 histone variant, and CENP-C, a foundational kinetochore protein, suggesting the de novo formation of a centromere on the chromatin fragment. To examine the sequences associated with CENH3, chromatin immunoprecipitation was carried out with anti-CENH3 antibodies using material from young seedlings with and without the Dp3a chromosome. A novel peak was detected from the ChIP-Sequencing reads of the Dp3a sample. The peak spanned 350 kb within the long arm of chromosome 3 covering 22 genes. Collectively, these results define the behavior and molecular features of de novo centromere formation in the Dp3a chromosome, which may shed light on the initiation of new centromere sites during evolution.
| S-EPMC3625319 | biostudies-literature
Project description:A small fragment from maize chromosome 3 was created by irradiation by Stadler and Roman and named Duplication 3a (or Dp3a). This small chromosome does not contain any detectable CentC and CRM sequences, but when molecular features of functional centromeres such as CENH3 and CENP-C were examined, they were present. Immunolocalization analysis of phosphorylation of Ser-10 of histone H3 levels on Dp3a shows a pattern typical of a functional centromere. Meiotic analysis revealed that sister chromatids divided equationally at meiosis I as do all small chromosomes examined to date in maize. To examine the sequences associated with CENH3, chromatin immunoprecipitation (ChIP) was carried out with anti-CENH3 antibodies using material from young seedlings with and without Dp3 chromosome as the tissue source. The ChIPed DNA sample was then labeled for FISH detection and prepared for Illumina sequencing.The ChIP-Seq reads were mapped to the B73 reference genome and a significant peak was detected in the Dp3a sample that span 350 kb of the long arm of chromosome 3, which is the candidate region for association with CENH3. ChIP-bisulfite-seq results indicated that there is a slightly increased DNA methylation level after the centromere formation, approaching the level similar to normal centromere regions. Collectively, the results suggest the formation of a de novo centromere on this fragment that initially must have started at the time of X-irradiation release from the progenitor chromosome. These observations add further evidence for the epigenetic nature of centromere function in maize.
2013-06-25 | GSE43138 | GEO
Project description:De novo assembly, annotation, and comparative analysis of 26 diverse maize genomes
| PRJNA697943 | ENA