Repetitive sequence analysis and karyotyping reveals centromere-associated DNA sequences in radish (Raphanus sativus L.). 2015

Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
Institute of Vegetables, Zhejiang Academy of Agricultural Sciences, Hangzhou, 310021, China. xiaoyuhqy@163.com.

BACKGROUND Radish (Raphanus sativus L., 2n = 2x = 18) is a major root vegetable crop especially in eastern Asia. Radish root contains various nutritions which play an important role in strengthening immunity. Repetitive elements are primary components of the genomic sequence and the most important factors in genome size variations in higher eukaryotes. To date, studies about repetitive elements of radish are still limited. To better understand genome structure of radish, we undertook a study to evaluate the proportion of repetitive elements and their distribution in radish. RESULTS We conducted genome-wide characterization of repetitive elements in radish with low coverage genome sequencing followed by similarity-based cluster analysis. Results showed that about 31% of the genome was composed of repetitive sequences. Satellite repeats were the most dominating elements of the genome. The distribution pattern of three satellite repeat sequences (CL1, CL25, and CL43) on radish chromosomes was characterized using fluorescence in situ hybridization (FISH). CL1 was predominantly located at the centromeric region of all chromosomes, CL25 located at the subtelomeric region, and CL43 was a telomeric satellite. FISH signals of two satellite repeats, CL1 and CL25, together with 5S rDNA and 45S rDNA, provide useful cytogenetic markers to identify each individual somatic metaphase chromosome. The centromere-specific histone H3 (CENH3) has been used as a marker to identify centromere DNA sequences. One putative CENH3 (RsCENH3) was characterized and cloned from radish. Its deduced amino acid sequence shares high similarities to those of the CENH3s in Brassica species. An antibody against B. rapa CENH3, specifically stained radish centromeres. Immunostaining and chromatin immunoprecipitation (ChIP) tests with anti-BrCENH3 antibody demonstrated that both the centromere-specific retrotransposon (CR-Radish) and satellite repeat (CL1) are directly associated with RsCENH3 in radish. CONCLUSIONS Proportions of repetitive elements in radish were estimated and satellite repeats were the most dominating elements. Fine karyotyping analysis was established which allow us to easily identify each individual somatic metaphase chromosome. Immunofluorescence- and ChIP-based assays demonstrated the functional significance of satellite and centromere-specific retrotransposon at centromeres. Our study provides a valuable basis for future genomic studies in radish.

UI MeSH Term Description Entries
D008677 Metaphase The phase of cell nucleus division following PROMETAPHASE, in which the CHROMOSOMES line up across the equatorial plane of the SPINDLE APPARATUS prior to separation.
D010940 Plant Proteins Proteins found in plants (flowers, herbs, shrubs, trees, etc.). The concept does not include proteins found in vegetables for which PLANT PROTEINS, DIETARY is available. Plant Protein,Protein, Plant,Proteins, Plant
D012091 Repetitive Sequences, Nucleic Acid Sequences of DNA or RNA that occur in multiple copies. There are several types: INTERSPERSED REPETITIVE SEQUENCES are copies of transposable elements (DNA TRANSPOSABLE ELEMENTS or RETROELEMENTS) dispersed throughout the genome. TERMINAL REPEAT SEQUENCES flank both ends of another sequence, for example, the long terminal repeats (LTRs) on RETROVIRUSES. Variations may be direct repeats, those occurring in the same direction, or inverted repeats, those opposite to each other in direction. TANDEM REPEAT SEQUENCES are copies which lie adjacent to each other, direct or inverted (INVERTED REPEAT SEQUENCES). DNA Repetitious Region,Direct Repeat,Genes, Selfish,Nucleic Acid Repetitive Sequences,Repetitive Region,Selfish DNA,Selfish Genes,DNA, Selfish,Repetitious Region, DNA,Repetitive Sequence,DNA Repetitious Regions,DNAs, Selfish,Direct Repeats,Gene, Selfish,Repeat, Direct,Repeats, Direct,Repetitious Regions, DNA,Repetitive Regions,Repetitive Sequences,Selfish DNAs,Selfish Gene
D002503 Centromere The clear constricted portion of the chromosome at which the chromatids are joined and by which the chromosome is attached to the spindle during cell division. Centromeres
D006657 Histones Small chromosomal proteins (approx 12-20 kD) possessing an open, unfolded structure and attached to the DNA in cell nuclei by ionic linkages. Classification into the various types (designated histone I, histone II, etc.) is based on the relative amounts of arginine and lysine in each. Histone,Histone H1,Histone H1(s),Histone H2a,Histone H2b,Histone H3,Histone H3.3,Histone H4,Histone H5,Histone H7
D016366 Open Reading Frames A sequence of successive nucleotide triplets that are read as CODONS specifying AMINO ACIDS and begin with an INITIATOR CODON and end with a stop codon (CODON, TERMINATOR). ORFs,Protein Coding Region,Small Open Reading Frame,Small Open Reading Frames,sORF,Unassigned Reading Frame,Unassigned Reading Frames,Unidentified Reading Frame,Coding Region, Protein,Frame, Unidentified Reading,ORF,Open Reading Frame,Protein Coding Regions,Reading Frame, Open,Reading Frame, Unassigned,Reading Frame, Unidentified,Region, Protein Coding,Unidentified Reading Frames
D017404 In Situ Hybridization, Fluorescence A type of IN SITU HYBRIDIZATION in which target sequences are stained with fluorescent dye so their location and size can be determined using fluorescence microscopy. This staining is sufficiently distinct that the hybridization signal can be seen both in metaphase spreads and in interphase nuclei. FISH Technique,Fluorescent in Situ Hybridization,Hybridization in Situ, Fluorescence,FISH Technic,Hybridization in Situ, Fluorescent,In Situ Hybridization, Fluorescent,FISH Technics,FISH Techniques,Technic, FISH,Technics, FISH,Technique, FISH,Techniques, FISH
D059785 Karyotype The full set of CHROMOSOMES presented as a systematized array of METAPHASE chromosomes from a photomicrograph of a single CELL NUCLEUS arranged in pairs in descending order of size and according to the position of the CENTROMERE. (From Stedman, 25th ed) Karyotypes
D018744 DNA, Plant Deoxyribonucleic acid that makes up the genetic material of plants. Plant DNA
D031224 Raphanus A plant genus of the family BRASSICACEAE known for its peppery red root. Radish,Cultivated Radish,Garden Radish,Radishes,Raphanus raphanistrum,Raphanus sativus,Wild Radish,Radish, Cultivated,Radish, Garden,Radish, Wild

Related Publications

Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
October 2014, DNA research : an international journal for rapid publication of reports on genes and genomes,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
June 2021, Scientific reports,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
May 2021, Plants (Basel, Switzerland),
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
September 1992, Plant physiology,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
May 2002, Phytochemistry,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
September 2017, Nutrients,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
May 2018, Planta,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
October 1974, Plant physiology,
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
August 2022, Plants (Basel, Switzerland),
Qunyan He, and Zexi Cai, and Tianhua Hu, and Huijun Liu, and Chonglai Bao, and Weihai Mao, and Weiwei Jin
June 1989, Plant physiology,
Copied contents to your clipboard!