2bv2
From Proteopedia
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==Overview== | ==Overview== | ||
| - | A refracting lens is a key component of our image-forming camera eye; | + | A refracting lens is a key component of our image-forming camera eye; however, its evolutionary origin is unknown because precursor structures appear absent in nonvertebrates. The vertebrate betagamma-crystallin genes encode abundant structural proteins critical for the function of the lens. We show that the urochordate Ciona intestinalis, which split from the vertebrate lineage before the evolution of the lens, has a single gene coding for a single domain monomeric betagamma-crystallin. The crystal structure of Ciona betagamma-crystallin is very similar to that of a vertebrate betagamma-crystallin domain, except for paired, occupied calcium binding sites. The Ciona betagamma-crystallin is only expressed in the palps and in the otolith, the pigmented sister cell of the light-sensing ocellus. The Ciona betagamma-crystallin promoter region targeted expression to the visual system, including lens, in transgenic Xenopus tadpoles. We conclude that the vertebrate betagamma-crystallins evolved from a single domain protein already expressed in the neuroectoderm of the prevertebrate ancestor. The conservation of the regulatory hierarchy controlling betagamma-crystallin expression between organisms with and without a lens shows that the evolutionary origin of the lens was based on co-option of pre-existing regulatory circuits controlling the expression of a key structural gene in a primitive light-sensing system. |
==About this Structure== | ==About this Structure== | ||
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[[Category: Ciona intestinalis]] | [[Category: Ciona intestinalis]] | ||
[[Category: Single protein]] | [[Category: Single protein]] | ||
| - | [[Category: Bateman, O | + | [[Category: Bateman, O A.]] |
| - | [[Category: Dirks, R | + | [[Category: Dirks, R P.H.]] |
| - | [[Category: Lubsen, N | + | [[Category: Lubsen, N H.]] |
| - | [[Category: Purkiss, A | + | [[Category: Purkiss, A G.]] |
| - | [[Category: Shimeld, S | + | [[Category: Shimeld, S M.]] |
[[Category: Slingsby, C.]] | [[Category: Slingsby, C.]] | ||
[[Category: ACT]] | [[Category: ACT]] | ||
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[[Category: spherulin]] | [[Category: spherulin]] | ||
| - | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on | + | ''Page seeded by [http://oca.weizmann.ac.il/oca OCA ] on Thu Feb 21 16:41:57 2008'' |
Revision as of 14:42, 21 February 2008
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BETA GAMMA CRYSTALLIN FROM CIONA INTESTINALIS
Overview
A refracting lens is a key component of our image-forming camera eye; however, its evolutionary origin is unknown because precursor structures appear absent in nonvertebrates. The vertebrate betagamma-crystallin genes encode abundant structural proteins critical for the function of the lens. We show that the urochordate Ciona intestinalis, which split from the vertebrate lineage before the evolution of the lens, has a single gene coding for a single domain monomeric betagamma-crystallin. The crystal structure of Ciona betagamma-crystallin is very similar to that of a vertebrate betagamma-crystallin domain, except for paired, occupied calcium binding sites. The Ciona betagamma-crystallin is only expressed in the palps and in the otolith, the pigmented sister cell of the light-sensing ocellus. The Ciona betagamma-crystallin promoter region targeted expression to the visual system, including lens, in transgenic Xenopus tadpoles. We conclude that the vertebrate betagamma-crystallins evolved from a single domain protein already expressed in the neuroectoderm of the prevertebrate ancestor. The conservation of the regulatory hierarchy controlling betagamma-crystallin expression between organisms with and without a lens shows that the evolutionary origin of the lens was based on co-option of pre-existing regulatory circuits controlling the expression of a key structural gene in a primitive light-sensing system.
About this Structure
2BV2 is a Single protein structure of sequence from Ciona intestinalis with , and as ligands. Known structural/functional Site: . Full crystallographic information is available from OCA.
Reference
Urochordate betagamma-crystallin and the evolutionary origin of the vertebrate eye lens., Shimeld SM, Purkiss AG, Dirks RP, Bateman OA, Slingsby C, Lubsen NH, Curr Biol. 2005 Sep 20;15(18):1684-9. PMID:16169492
Page seeded by OCA on Thu Feb 21 16:41:57 2008
Categories: Ciona intestinalis | Single protein | Bateman, O A. | Dirks, R P.H. | Lubsen, N H. | Purkiss, A G. | Shimeld, S M. | Slingsby, C. | ACT | CA | SO4 | Ascidian | Calcium binding | Chordate | Crystallin | Eye lens | Spherulin
