Cloning and molecular characterization of a telomeric sequence from a temperature-induced Balbiani ring

Carmona, Manuel; Morcillo, Gloria; Galler, Ricardo; Martínez‐Salas, Encarnación; Campa, Adela G. de la; Díez, J. L.; Edström, J.-E.

doi:10.1007/bf00328462

Cited by 49 publications

(74 citation statements)

References 29 publications

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“…3). A unit of this size still exists in C. thummi thummi (8). The simple monomeric unit has a base composition that might make the DNA particularly susceptible to insertion of retroposons in agreement with a model by Rogers (27) in which T-or T+G-rich sequences could be used after a nick in the DNA to prime an mRNA from the poly(A) tail.…”

Section: Methodssupporting

confidence: 73%

“…Such DNA of different origin has one feature in common: all or most of the cytosines are in one strand and the guanines in the other. The terminal DNA can be added to the ends enzymatically by telomerase (17,18) (8,9,24,29). Similar DNA has also been described for some Drosophila species (1).…”

mentioning

confidence: 82%

“…Starting at the end of L3, there are five rather evenly spaced degenerate subrepeats up to the beginning of the region with a low C/G ratio, (2) GCTCTA (12) CGTCAT (3) CCTCAA (13) CCTCAA (4) TATAAA (14) TCTCAA (5) CATCGA (15) TCTCAT (6) TCTGCA (7) Tl TCAC (8) CCTTAA (9) TCTCAA (10) Consensus:…”

Section: Methodsmentioning

confidence: 99%

“…In chironomids, DNA at or close to the chromosome ends, TA DNA, consists of regular tandem arrays (8,9,24,29). Similar DNA has also been described for some Drosophila species (1).…”

mentioning

confidence: 98%

“…No such DNA has been found in dipteran species. The telomere-associated (TA) DNA recovered in Drosophila species (1,3,4,26,28,34) and Chironomus species (8,9,24,29) is more complex, like subtelomeric DNA in other species. It will be difficult to exclude that a few short repeats, of potential functional importance, remain undetected at the ends of dipteran chromosomes.…”

mentioning

confidence: 99%

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Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

Nielsen¹,

Edström²

1993

Mol. Cell. Biol.

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The dipteran Chironomus tentans has complex tandemly repeated 350-bp DNA sequences at or near the chromosome ends. As in Drosophila melanogaster, short simple repeats with cytosines and guanines in different strands have never been observed. We were therefore interested in learning whether the Chironomus repeats could have evolved from simple sequence telomeric DNA, which might suggest that they constitute a functional equivalent. We screened for repeat units with evolutionarily ancient features within the tandem arrays and recovered two clones with a less-evolved structure. Sequence analysis reveals that the present-day 350-bp unit probably evolved from a simpler 165-bp unit through the acquisition of transposed sequences. The 165-bp unit contains DNA with a highly biased distribution of cytosine and guanine between the two strands, although with the ratios inverted in two minor parts of the repeat. It is largely built up of short degenerate subrepeats for which most of the sequence can be reconstructed. The consensus for the subrepeat sequence is similar to the simple telomeric repeat sequences of several kinds of eukaryotes. We propose that the present-day unit has evolved from telomeric, simple sequence, asymmetric DNA from which it has retained some original sequence features and possibly functions.At the ends of most eukaryotic chromosomes, there are short, simple DNA repeats, slightly different in various lower and higher eukaryotes (reviewed in reference 5). Such DNA of different origin has one feature in common: all or most of the cytosines are in one strand and the guanines in the other. The terminal DNA can be added to the ends enzymatically by telomerase (17,18) (8,9,24,29). Similar DNA has also been described for some Drosophila species (1). Because of the well-defined structure of the 350-bp TA repeats in the subgenus Camptochironomus, with two pairs of subrepeats in an alternating arrangement, separated by four linker regions, nonrepetitive within the 350-bp unit, the TA repeats provide an interesting model to learn how a complex unit is formed during evolution from a simpler organization. We have earlier asked whether the formation of subrepeats, which show more than 90% mutual homology, is due to differences in rates of evolution along the 350-bp repeat unit after previous duplication of an approximately 175-bp half-repeat. Alternatively, forces exist * Corresponding author.that give members of a pair of subrepeats a parallel evolution. We have compared repeat units in the closely related Chironomus tentans and C. pallidivittatus and concluded that mutations are preferentially located in linker regions, thus supporting the first alternative (24).From the interspecies comparison, we learned what happened after speciation, when most of the morphology of the repeat unit is already established. For present purposes, we searched for a repeat unit with early evolutionary characters. For tandem repeats, this is not necessarily unrealistic, since tandem repeats may contain units at their ends representi...

show abstract

Section: Methodssupporting

confidence: 73%

mentioning

confidence: 82%

Section: Methodsmentioning

confidence: 99%

“…In chironomids, DNA at or close to the chromosome ends, TA DNA, consists of regular tandem arrays (8,9,24,29). Similar DNA has also been described for some Drosophila species (1).…”

mentioning

confidence: 98%

mentioning

confidence: 99%

See 3 more Smart Citations

Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

Nielsen¹,

Edström²

1993

Mol. Cell. Biol.

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The 93D (hsr-omega) locus of Drosophila: non-coding gene with house-keeping functions

Lakhotia

Sharma

1996

Genetica

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The 93D, or hsr-omega (heat-shock RNA-omega), locus of Drosophila melanogaster and other species of Drosophila, besides being induced as a member of the heat shock gene family, is also selectively and singularly inducible by a variety of agents, notably benzamide, colchicine and vitamin B6 (in species other than D. melanogaster). The genomic structure of this locus is highly conserved in all species, although the primary base sequence has diverged rapidly between species. Three transcripts (two nuclear and one cytoplasmic) are produced by this locus but none of them has any significant protein coding capacity. The profile of the three transcripts varies in a developmental and inducer-specific manner. This locus is developmentally active in nearly all cell types and is essential for viability of flies. Its induction during heat shock is independent of the other members of the heat shock gene family. The other selective inducers act on this locus through separate response elements. hsr-omega activity has a characteristic effect on transcription/turnover of the heat shock induced hsp70 and the alpha-beta transcripts in D. melanogaster. It appears that the hsr-omega locus has important house-keeping functions in transport and turnover of some transcripts and in monitoring the 'health' of the translational machinery of the cell.

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Telomere-associated repeats in Chironomus form discrete subfamilies generated by gene conversion

Cohn

Edström

1992

J Mol Evol

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In dipteran insects the most distal telomere-associated DNA known to exist consists of long, complex tandem repeats. We have classified the 340-bp tandemly arranged repeats in Chironomus pallidivittatus. The repeats are distributed in a small number of subfamilies. One type of the repeat has the character of a master unit from which other main units can be derived usually by simple changes. The derived subfamilies contain segments that are degenerate versions of the corresponding segment in the master sequence. Such segments can also occur together in one and the same repeat unit in different combinations. There is a complete absence of subfamily-specific base variants in regions lying outside of the degenerate segments. Homogenization takes place between DNA sequences that are often smaller than a whole repeat unit. The mosaic structure of the repeat arrays suggests that gene conversion is an important force in the generation and maintenance of this family of repeats.

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Cloning and molecular characterization of a telomeric sequence from a temperature-induced Balbiani ring

Cited by 49 publications

References 29 publications

Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

Complex telomere-associated repeat units in members of the genus Chironomus evolve from sequences similar to simple telomeric repeats.

The 93D (hsr-omega) locus of Drosophila: non-coding gene with house-keeping functions

Telomere-associated repeats in Chironomus form discrete subfamilies generated by gene conversion

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