scholarly journals Long Tandem Arrays of Cassandra Retroelements and Their Role in Genome Dynamics in Plants

2020 ◽  
Vol 21 (8) ◽  
pp. 2931 ◽  
Author(s):  
Ruslan Kalendar ◽  
Olga Raskina ◽  
Alexander Belyayev ◽  
Alan H. Schulman
Keyword(s):  
Copy Number ◽  
5S Rdna ◽  
5S Rrna ◽  
Rrna Genes ◽  
Gene Copy ◽  
Rrna Gene ◽  
Long Terminal Repeats ◽  
5S Rrna Genes ◽  
Pol Iii ◽  
Tandem Arrays

Retrotransposable elements are widely distributed and diverse in eukaryotes. Their copy number increases through reverse-transcription-mediated propagation, while they can be lost through recombinational processes, generating genomic rearrangements. We previously identified extensive structurally uniform retrotransposon groups in which no member contains the gag, pol, or env internal domains. Because of the lack of protein-coding capacity, these groups are non-autonomous in replication, even if transcriptionally active. The Cassandra element belongs to the non-autonomous group called terminal-repeat retrotransposons in miniature (TRIM). It carries 5S RNA sequences with conserved RNA polymerase (pol) III promoters and terminators in its long terminal repeats (LTRs). Here, we identified multiple extended tandem arrays of Cassandra retrotransposons within different plant species, including ferns. At least 12 copies of repeated LTRs (as the tandem unit) and internal domain (as a spacer), giving a pattern that resembles the cellular 5S rRNA genes, were identified. A cytogenetic analysis revealed the specific chromosomal pattern of the Cassandra retrotransposon with prominent clustering at and around 5S rDNA loci. The secondary structure of the Cassandra retroelement RNA is predicted to form super-loops, in which the two LTRs are complementary to each other and can initiate local recombination, leading to the tandem arrays of Cassandra elements. The array structures are conserved for Cassandra retroelements of different species. We speculate that recombination events similar to those of 5S rRNA genes may explain the wide variation in Cassandra copy number. Likewise, the organization of 5S rRNA gene sequences is very variable in flowering plants; part of what is taken for 5S gene copy variation may be variation in Cassandra number. The role of the Cassandra 5S sequences remains to be established.

scholarly journals Molecular organization of 5S rDNA intergenic spacer in Gentiana pneumonanthe L. and G. punctata L.

2021 ◽  
Vol 18 (1-2) ◽  
pp. 9-15
Author(s):  
V. M. Mel’nyk ◽  
I. O. Andreev ◽  
G. Yu. Myryuta ◽  
A. Y. Shelyfist ◽  
R. A. Volkov ◽  
...  
Keyword(s):  
Intergenic Spacer ◽  
5S Rdna ◽  
5S Rrna ◽  
Molecular Organization ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Coding Region ◽  
5S Rrna Genes ◽  
Rdna Igs ◽  
Rdna Intergenic Spacer

Aim. The study was aimed at cloning and analysis of molecular organization of 5S rDNA intergenic spacer (IGS) in two Gentiana species of Ukrainian flora, G. pneumonanthe L. and G. punctata L. Methods. 5S rDNA IGS sequence was amplified using polymerase chain reaction (PCR) with a pair of primers specific for the gene coding region. The produced PCR products were fractionated by gel-electrophoresis, isolated, ligated into plasmid pUC18, cloned into E. coli, and then sequenced. Nucleotide sequences were aligned using the Muscle algorithm and analyzed in the Unipro UGENE software. Results. The intergenic spacer region of the 5S rRNA genes was cloned and sequenced for two Gentiana species of Ukrainian flora, G. pneumonanthe and G. punctata. Based on the analysis of the alignment of the IGS sequences of five Gentiana species from three sections, some features of molecular organization of IGS of 5S rRNA genes in the studied species were established. In particular, motifs typical for other angiosperm families were identified, such as conservative oligo-dT motif at the IGS 3'-end that served as a transcription termination site and AT-rich region preceding the coding region of 5S rRNA gene. However, in the region of transcription initiation, conservative GC-element in position -13 is changed to AC. Conclusions. The interspecific variation of molecular organization of 5S rDNA IGS was identified among Gentiana species that can be used to clarify the phylogenetic relationships between members of this genus.Keywords: Gentiana species, 5S rDNA intergenic spacer, molecular organization, phylogeny.

5S rRNA genes in tribe Phaseoleae: array size, number, and dynamics

Genome ◽  
1996 ◽  
Vol 39 (2) ◽  
pp. 445-455 ◽  
Author(s):  
Kathleen J. Danna ◽  
Rachel Workman ◽  
Virginia Coryell ◽  
Paul Keim
Keyword(s):  
Gel Electrophoresis ◽  
Copy Number ◽  
Glycine Soja ◽  
Repeat Unit ◽  
Diploid Species ◽  
5S Rdna ◽  
5S Rrna ◽  
Array Size ◽  
Rrna Genes ◽  
5S Rrna Genes

The organization of 5S rRNA genes in plants belonging to tribe Phaseoleae was investigated by clamped homogeneous electric field gel electrophoresis and Southern blot hybridization. Representatives of subtribe Glycininae included the diploid species Neonotonia wightii and Teramnus labialis, as well as three soybean accessions: an elite Glycine max (L.) Merr. cultivar (BSR101), an unadapted G. max introduction (PI 437.654), and a wild Glycine soja (PI 468.916). A cultivar of Phaseolus vulgaris (kidney bean), a member of subtribe Phaseolinae, was also examined. We determined the number of 5S rDNA arrays and estimated the size and copy number of the repeat unit for each array. The three soybean accessions all have a single 5S locus, with a repeat unit size of ~345 bp and a copy number ranging from about 600 in 'BSR101' to about 4600 in the unadapted soybean introduction. The size of the 5S gene cluster in 'BSR101' is the same in roots, shoots, and trifoliate leaves. Given that the genus Glycine probably has an allotetraploid origin, our data strongly suggest that one of the two progenitor 5S loci has been lost during diploidization of soybean. Neonotonia wightii, the diploid species most closely related to soybean, also has a single locus but has a repeat unit of 520 bp and a copy number of about 1300. The more distantly related species T. labialis and P. vulgaris exhibited a more complex arrangement of 5S rRNA genes, having at least three arrays, each comprising a few hundred copies of a distinct repeat unit. Although each array in P. vulgaris exhibits a high degree of homogeneity with regard to the sequence of the repeat unit, heterogeneity in array size (copy number) was evident when individual plants were compared. A cis-dependent molecular drive process, such as unequal crossing-over, could account for both the homogenization of repeat units within individual arrays and the observed variation in copy number among individuals. Key words : pulsed-field gel electrophoresis, rRNA genes, soybean, tandem arrays.

Organization of 5S ribosomal RNA genes in tea (Camellia sinensis)

Genome ◽  
2001 ◽  
Vol 44 (1) ◽  
pp. 143-146 ◽  
Author(s):  
Dharam Singh ◽  
Mahipal Singh
Keyword(s):  
Camellia Sinensis ◽  
Tandem Repeats ◽  
5S Rdna ◽  
5S Rrna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Repeat Units ◽  
Camellia Species ◽  
5S Rrna Genes ◽  
Rna Genes

The 5S rRNA genes in the Camellia sinensis (L.) O. Kuntze (tea) genome are arranged as tandem repeat units of 300 and 325 bps. The 2 classes of tandem repeats were discovered by Southern hybridisation of tea genomic DNA with a 5S rRNA gene PCR product.Key words: Camellia species, 5S rDNA, multigene family, tandem repeats, spacers.

Molecular characterization of 5S ribosomal RNA genes and transcripts in the protozoan parasite Leishmania major

Parasitology ◽  
2016 ◽  
Vol 143 (14) ◽  
pp. 1917-1929 ◽  
Author(s):  
RODRIGO MORENO-CAMPOS ◽  
LUIS E. FLORENCIO-MARTÍNEZ ◽  
TOMÁS NEPOMUCENO-MEJÍA ◽  
SAÚL ROJAS-SÁNCHEZ ◽  
DANIEL E. VÉLEZ-RAMÍREZ ◽  
...  
Keyword(s):  
Leishmania Major ◽  
Rna Polymerase Iii ◽  
Nuclear Periphery ◽  
Ribosomal Subunit ◽  
Protozoan Parasite ◽  
5S Rrna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
5S Rrna Genes ◽  
Pol Iii

SUMMARYEukaryotic 5S rRNA, synthesized by RNA polymerase III (Pol III), is an essential component of the large ribosomal subunit. Most organisms contain hundreds of 5S rRNA genes organized into tandem arrays. However, the genome of the protozoan parasite Leishmania major contains only 11 copies of the 5S rRNA gene, which are interspersed and associated with other Pol III-transcribed genes. Here we report that, in general, the number and order of the 5S rRNA genes is conserved between different species of Leishmania. While in most organisms 5S rRNA genes are normally associated with the nucleolus, combined fluorescent in situ hybridization and indirect immunofluorescence experiments showed that 5S rRNA genes are mainly located at the nuclear periphery in L. major. Similarly, the tandemly repeated 5S rRNA genes in Trypanosoma cruzi are dispersed throughout the nucleus. In contrast, 5S rRNA transcripts in L. major were localized within the nucleolus, and scattered throughout the cytoplasm, where mature ribosomes are located. Unlike other rRNA species, stable antisense RNA complementary to 5S rRNA is not detected in L. major.

scholarly journals Ribosomal DNA localization on Lathyrus species chromosomes by FISH

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Hoda B. M. Ali ◽  
Samira A. Osman
Keyword(s):  
Genome Mapping ◽  
Chromosome Complement ◽  
5S Rdna ◽  
Rdna Locus ◽  
5S Rrna ◽  
Rrna Genes ◽  
45S Rdna ◽  
Metaphase Chromosomes ◽  
Lathyrus Odoratus ◽  
5S Rrna Genes

Abstract Background Fluorescence In Situ Hybridization (FISH) played an essential role to locate the ribosomal RNA genes on the chromosomes that offered a new tool to study the chromosome structure and evolution in plant. The 45S and 5S rRNA genes are independent and localized at one or more loci per the chromosome complement, their positions along chromosomes offer useful markers for chromosome discriminations. In the current study FISH has been performed to locate 45S and 5S rRNA genes on the chromosomes of nine Lathyrus species belong to five different sections, all have chromosome number 2n=14, Lathyrus gorgoni Parl, Lathyrus hirsutus L., Lathyrus amphicarpos L., Lathyrus odoratus L., Lathyrus sphaericus Retz, Lathyrus incospicuus L, Lathyrus paranensis Burkart, Lathyrus nissolia L., and Lathyrus articulates L. Results The revealed loci of 45S and 5S rDNA by FISH on metaphase chromosomes of the examined species were as follow: all of the studied species have one 45S rDNA locus and one 5S rDNA locus except L. odoratus L., L. amphicarpos L. and L. sphaericus Retz L. have two loci of 5S rDNA. Three out of the nine examined species have the loci of 45S and 5S rRNA genes on the opposite arms of the same chromosome (L. nissolia L., L. amphicarpos L., and L. incospicuus L.), while L. hirsutus L. has both loci on the same chromosome arm. The other five species showed the loci of the two types of rDNA on different chromosomes. Conclusion The detected 5S and 45S rDNA loci in Lathyrus could be used as chromosomal markers to discriminate the chromosome pairs of the examined species. FISH could discriminate only one chromosome pair out of the seven pairs in three species, in L. hirsutus L., L. nissolia L. and L. incospicuus L., and two chromosome pairs in five species, in L. paranensis Burkart, L. odoratus L., L. amphicarpos L., L. gorgoni Parl. and L. articulatus L., while it could discriminate three chromosome pairs in L. sphaericus Retz. these results could contribute into the physical genome mapping of Lathyrus species and the evolution of rDNA patterns by FISH in the coming studies in future.

A natural case of RIP: degeneration of the DNA sequence in an ancestral tandem duplication

1989 ◽  
Vol 9 (10) ◽  
pp. 4416-4421
Author(s):  
W S Grayburn ◽  
E U Selker
Keyword(s):  
Dna Methylation ◽  
Tandem Duplication ◽  
De Novo ◽  
5S Rrna ◽  
Rrna Genes ◽  
Structural Basis ◽  
Rrna Gene ◽  
Oak Ridge ◽  
5S Rrna Gene ◽  
5S Rrna Genes

5S rRNA genes of Neurospora crassa are generally dispersed in the genome and are unmethylated. The xi-eta region of Oak Ridge strains represents an informative exception. Most of the cytosines in this region, which consists of a diverged tandem duplication of a 0.8-kilobase-pair segment including a 5S rRNA gene, appear to be methylated (E. U. Selker and J. N. Stevens, Proc. Natl. Acad. Sci. USA 82:8114-8118, 1985). Previous work demonstrated that the xi-eta region functions as a portable signal for de novo DNA methylation (E. U. Selker and J. N. Stevens, Mol. Cell. Biol. 7:1032-1038, 1987; E. U. Selker, B. C. Jensen, and G. A. Richardson, Science 238:48-53, 1987). To identify the structural basis of this property, we have isolated and characterized an unmethylated allele of the xi-eta region from N. crassa Abbott 4. The Abbott 4 allele includes a single 5S rRNA gene, theta, which is different from all previously identified Neurospora 5S rRNA genes. Sequence analysis suggests that the xi-eta region arose from the theta region by duplication of a 794-base-pair segment followed by 267 G.C to A.T mutations in the duplicated DNA. The distribution of these mutations is not random. We propose that the RIP process of N. crassa (E. U. Selker, E. B. Cambareri, B. C. Jensen, and K. R. Haack, Cell 51:741-752, 1987; E. U. Selker, and P. W. Garrett, Proc. Natl. Acad. Sci. USA 85:6870-6874, 1988; E. B. Cambareri, B. C. Jensen, E. Schabtach, and E. U. Selker, Science 244:1571-1575, 1989) is responsible for the numerous transition mutations and DNA methylation in the xi-eta region. A long homopurine-homopyrimidine stretch immediately following the duplicated segment is 9 base pairs longer in the Oak Ridge allele than in the Abbott 4 allele. Triplex DNA, known to occur in homopurine-homopyrimidine sequences, may have mediated the tandem duplication.

Localization of the 5S rRNA genes and evidence for diversity in the 5S rDNA region of maize

Gene ◽  
1981 ◽  
Vol 15 (1) ◽  
pp. 7-20 ◽  
Author(s):  
P.N. Mascia ◽  
I. Rubenstein ◽  
R.L. Phillips ◽  
A.S. Wang ◽  
Lu Zhen Xiang
Keyword(s):  
5S Rdna ◽  
5S Rrna ◽  
Rrna Genes ◽  
5S Rrna Genes

Genetic and chromosomal localization of the 5S rDNA locus in sugar beet (Beta vulgaris L.)

Genome ◽  
1997 ◽  
Vol 40 (2) ◽  
pp. 171-175 ◽  
Author(s):  
J. Schondelmaier ◽  
T. Schmidt ◽  
C. Jung ◽  
J. S. Heslop-Harrison
Keyword(s):  
In Situ Hybridization ◽  
Linkage Group ◽  
Sugar Beet ◽  
Beta Vulgaris ◽  
5S Rdna ◽  
Rdna Locus ◽  
5S Rrna ◽  
Rrna Genes ◽  
Rrna Gene

A digoxigenin-labelled 5S rDNA probe containing the 5S rRNA gene and the adjacent intergenic spacer was used for in situ hybridization to metaphase and interphase chromosomes of a trisomic stock from sugar beet (Beta vulgaris L.). Three chromosomes of primary trisomic line IV (T. Butterfass. Z. Bot. 52: 46–77. 1964) revealed signals close to the centromeres. Polymorphisms of 5S rDNA repeats in a segregating population were used to map genetically the 5S rRNA genes within a cluster of markers in linkage group II of sugar beet. The concentration of genetic markers around the centromere presumably reflects the suppressed recombination frequency in centromeric regions. The correlation of physical and genetic data allowed the assignment of a linkage group to sugar beet chromosome IV according to line IV of the primary trisomics.Key words: Beta vulgaris, sugar beet, 5S rRNA, in situ hybridization, RFLPs, trisomics.

The 5S rRNA gene units in ancestral two-rowed barley (Hordeum spontaneum C. Koch) and bulbous barley (H. bulbosum L.): sequence analysis and phylogenetic relationships with the 5S rDNA units of cultivated barley (H. vulgare L.)

Genome ◽  
1996 ◽  
Vol 39 (1) ◽  
pp. 140-149 ◽  
Author(s):  
Bernard R. Baum ◽  
Douglas A. Johnson
Keyword(s):  
Phylogenetic Analysis ◽  
5S Rdna ◽  
Hordeum Spontaneum ◽  
Wild Relatives ◽  
5S Rrna ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Sequence Comparisons ◽  
Rdna Sequences ◽  
Cultivated Barley

5S rRNA genes from several accessions of Hordeum spontaneum and Hordeum bulbosum, wild relatives of cultivated barley, Hordeum vulgare, have been amplified by the polymerase chain reaction, cloned, and sequenced. Evaluation of aligned sequences along with principal coordinate analysis demonstrates that the two classes of 5S rDNA sequences found in cultivated barley, and subclasses (groups) of these sequences, can also be found in its closest wild relatives. The two classes of units, formerly categorized as containing short or long 5S rDNA repeats, are distinguishable by the presence or absence of a TAG repeating unit. Sequence comparisons of individual clones (units) isolated from different species have allowed us to confirm that orthology exists for several groups. This demonstration of orthologous groups suggests that the 5S rDNA sequence may be useful for further phylogenetic analysis in the genus Hordeum and possibly in the Triticeae. Key words : 5S rDNA, barley, sequence diversity, phylogenetic analysis.

Molecular characterization and chromosomal mapping of the 5S rRNA gene in Solea senegalensis: a new linkage to the U1, U2, and U5 small nuclear RNA genes

Genome ◽  
2006 ◽  
Vol 49 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Manuel Manchado ◽  
Eugenia Zuasti ◽  
Ismael Cross ◽  
Alejandro Merlo ◽  
Carlos Infante ◽  
...  
Keyword(s):  
5S Rdna ◽  
5S Rrna ◽  
Rrna Genes ◽  
Solea Senegalensis ◽  
Rrna Gene ◽  
Small Nuclear Rna ◽  
5S Rrna Gene ◽  
Nuclear Rna ◽  
Pcr Products ◽  
Rna Genes

Some units of the 5S rDNA of Solea senegalensis were amplified by PCR and sequenced. Three main PCR products (227, 441, and 2166 bp) were identified. The 227- and 441-bp fragments were characterized by highly divergent nontranscribed spacer sequences (referred to as NTS-I and NTS-II) that were 109 and 324 bp long, respectively, yet their coding sequences were nearly identical. The 2166-bp 5S rDNA unit was composed of two 5S rRNA genes separated by NTS-I and followed by a 1721-bp spacer containing the U2, U5, and U1 small nuclear RNA genes (snRNAs). They were inverted and arranged in the transcriptional direction opposite that of the 5S rRNA gene. This simultaneous linkage of 3 different snRNAs had never been observed before. The PCR products were used as probes in fluorescence in situ hybridization experiments to locate the corresponding loci on the chromosomes of S. senegalensis. A major 5S rDNA chromosomal site was located along most of the short arm of a submetacentric pair, while a minor site was detected near the centromeric region of an acrocentric pair.Key words: soleidae, pleuronectiformes, 5S rDNA, Solea, snRNAs linkage.

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