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Cross-Species Interaction between Rapidly Evolving Telomere-Specific Drosophila Proteins.

Vedelek B, Blastyák A, Boros IM - PLoS ONE (2015)

Bottom Line: The accelerated evolution of terminin components may indicate the involvement of these proteins in the process by which new species arise, as the resulting divergence of terminin proteins might prevent hybrid formation, thus driving speciation.Our results suggest formation of stable subcomplexes of terminin, but not of the whole complex in vitro.We found that the accelerated evolution is restricted to definable regions of terminin components, and that the divergence of D. melanogaster Drosophila Telomere Loss and D. yakuba Verrocchio proteins does not preclude their stable interaction.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary.

ABSTRACT
Telomere integrity in Drosophila melanogaster is maintained by a putative multisubunit complex called terminin that is believed to act in analogy to the mammalian shelterin complex in protecting chromosome ends from being recognized as sites of DNA damage. The five proteins supposed to form the terminin complex are HP1-ORC associated protein, HP1-HOAP interacting protein, Verrocchio, Drosophila Telomere Loss/Modigliani and Heterochromatic Protein 1. Four of these proteins evolve rapidly within the Drosophila genus. The accelerated evolution of terminin components may indicate the involvement of these proteins in the process by which new species arise, as the resulting divergence of terminin proteins might prevent hybrid formation, thus driving speciation. However, terminin is not an experimentally proven entity, and no biochemical studies have been performed to investigate its assembly and action in detail. Motivated by these facts in order to initiate biochemical studies on terminin function, we attempted to reconstitute terminin by co-expressing its subunits in bacteria and investigated the possible role of the fast-evolving parts of terminin components in complex assembly. Our results suggest formation of stable subcomplexes of terminin, but not of the whole complex in vitro. We found that the accelerated evolution is restricted to definable regions of terminin components, and that the divergence of D. melanogaster Drosophila Telomere Loss and D. yakuba Verrocchio proteins does not preclude their stable interaction.

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Related in: MedlinePlus

Ver and DTL/Moi form a heterodimer that could be purified independently from other terminin proteins.(A) Heparin-sepharose chromatography fractions of co-expressed Ver and DTL/Moi. Different parts of the same gel are shown. (B) The first 5 fractions of the purification shown on panel A containing Ver and DTL/Moi proteins were combined and gel-filtrated on Superdex 200 10/300 GL column. Molecular weight marker (L), input (Inp), flow through (FT) and fraction numbers and the position of the respected proteins are indicated.
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pone.0142771.g005: Ver and DTL/Moi form a heterodimer that could be purified independently from other terminin proteins.(A) Heparin-sepharose chromatography fractions of co-expressed Ver and DTL/Moi. Different parts of the same gel are shown. (B) The first 5 fractions of the purification shown on panel A containing Ver and DTL/Moi proteins were combined and gel-filtrated on Superdex 200 10/300 GL column. Molecular weight marker (L), input (Inp), flow through (FT) and fraction numbers and the position of the respected proteins are indicated.

Mentions: Mixing the peak fractions that eluted from the heparin-sepharose matrix at low salt did not change the profile of the subsequent gel filtration, indicating that the elution of Ver-DTL/Moi and HOAP-HP1 in two peaks from heparin-sepharose is not due to the increasing salt concentration used during development of the column (Fig 4C). The formation of a stable heterodimer of Ver and DTL/Moi was also verified by processing the soluble fraction from bicistronic expression similarly as described above: Ver and DTL/Moi were bound to a heparin-sepharose column and eluted at low NaCl concentration (Fig 5A). During gel filtration Ver and DTL/Moi proteins co-migrated as one single peak corresponding to a 45 kDa mass, which contained the two proteins in 1:1 ratio as expected (Fig 5B).


Cross-Species Interaction between Rapidly Evolving Telomere-Specific Drosophila Proteins.

Vedelek B, Blastyák A, Boros IM - PLoS ONE (2015)

Ver and DTL/Moi form a heterodimer that could be purified independently from other terminin proteins.(A) Heparin-sepharose chromatography fractions of co-expressed Ver and DTL/Moi. Different parts of the same gel are shown. (B) The first 5 fractions of the purification shown on panel A containing Ver and DTL/Moi proteins were combined and gel-filtrated on Superdex 200 10/300 GL column. Molecular weight marker (L), input (Inp), flow through (FT) and fraction numbers and the position of the respected proteins are indicated.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4643883&req=5

pone.0142771.g005: Ver and DTL/Moi form a heterodimer that could be purified independently from other terminin proteins.(A) Heparin-sepharose chromatography fractions of co-expressed Ver and DTL/Moi. Different parts of the same gel are shown. (B) The first 5 fractions of the purification shown on panel A containing Ver and DTL/Moi proteins were combined and gel-filtrated on Superdex 200 10/300 GL column. Molecular weight marker (L), input (Inp), flow through (FT) and fraction numbers and the position of the respected proteins are indicated.
Mentions: Mixing the peak fractions that eluted from the heparin-sepharose matrix at low salt did not change the profile of the subsequent gel filtration, indicating that the elution of Ver-DTL/Moi and HOAP-HP1 in two peaks from heparin-sepharose is not due to the increasing salt concentration used during development of the column (Fig 4C). The formation of a stable heterodimer of Ver and DTL/Moi was also verified by processing the soluble fraction from bicistronic expression similarly as described above: Ver and DTL/Moi were bound to a heparin-sepharose column and eluted at low NaCl concentration (Fig 5A). During gel filtration Ver and DTL/Moi proteins co-migrated as one single peak corresponding to a 45 kDa mass, which contained the two proteins in 1:1 ratio as expected (Fig 5B).

Bottom Line: The accelerated evolution of terminin components may indicate the involvement of these proteins in the process by which new species arise, as the resulting divergence of terminin proteins might prevent hybrid formation, thus driving speciation.Our results suggest formation of stable subcomplexes of terminin, but not of the whole complex in vitro.We found that the accelerated evolution is restricted to definable regions of terminin components, and that the divergence of D. melanogaster Drosophila Telomere Loss and D. yakuba Verrocchio proteins does not preclude their stable interaction.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Molecular Biology, University of Szeged, Szeged, Hungary.

ABSTRACT
Telomere integrity in Drosophila melanogaster is maintained by a putative multisubunit complex called terminin that is believed to act in analogy to the mammalian shelterin complex in protecting chromosome ends from being recognized as sites of DNA damage. The five proteins supposed to form the terminin complex are HP1-ORC associated protein, HP1-HOAP interacting protein, Verrocchio, Drosophila Telomere Loss/Modigliani and Heterochromatic Protein 1. Four of these proteins evolve rapidly within the Drosophila genus. The accelerated evolution of terminin components may indicate the involvement of these proteins in the process by which new species arise, as the resulting divergence of terminin proteins might prevent hybrid formation, thus driving speciation. However, terminin is not an experimentally proven entity, and no biochemical studies have been performed to investigate its assembly and action in detail. Motivated by these facts in order to initiate biochemical studies on terminin function, we attempted to reconstitute terminin by co-expressing its subunits in bacteria and investigated the possible role of the fast-evolving parts of terminin components in complex assembly. Our results suggest formation of stable subcomplexes of terminin, but not of the whole complex in vitro. We found that the accelerated evolution is restricted to definable regions of terminin components, and that the divergence of D. melanogaster Drosophila Telomere Loss and D. yakuba Verrocchio proteins does not preclude their stable interaction.

Show MeSH
Related in: MedlinePlus