Evidence for the extralenticular expression of members of the β-crystallin gene family in the chick and a comparison with δ-crystallin during differentiation and transdifferentiation

Head, Mark W.; Peter, Audrey; Clayton, R. M.

doi:10.1111/j.1432-0436.1991.tb00253.x

Cited by 54 publications

(18 citation statements)

References 59 publications

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“…A more thorough analysis of expression patterns of the large P-crystallin family is required, although transcripts from at least two 3-crystallin genes have been detected in the developing chicken retina, at levels between 1 and 0.1% of that found in the lens (16). For a-crystallins, with only two family members, the analysis is more complete, and it is clear that a somewhat different expression profile is exhibited from that observed for Xenopus -y-crystallins.…”

Section: Resultsmentioning

confidence: 99%

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Xenopus gamma-crystallin gene expression: evidence that the gamma-crystallin gene family is transcribed in lens and nonlens tissues.

et al. 1994

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Crystallins, the major gene products of the lens, accumulate to high levels during the differentiation of the vertebrate lens. Although crystallins were traditionally thought to be lens specific, it has recently been shown that some are also expressed at very low levels in nonlens tissues. We have examined the embryonic expression pattern of gamma-crystallins, the most abundant crystallins of the embryonic lens in Xenopus laevis. The expression profile of five Xenopus gamma-crystallin genes mirrors the pattern of lens differentiation in X. laevis, exhibiting on average a 100-fold increase between tailbud and tadpole stages. Four of these genes are also ubiquitously expressed outside the lens at a very low level, the first demonstration of nonlens expression of any gamma-crystallin gene; expression of the remaining gene was not detected outside the head region, thus suggesting that there may be two classes of gamma-crystallin genes in X. laevis. Predictions regarding control mechanisms responsible for this dual mode of expression are discussed. This study raises the question of whether any crystallin, on stringent examination, will be found exclusively in the lens.

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Section: Resultsmentioning

confidence: 99%

“…(19,41,42). Two members of the large and heterogeneous 3-crystallin family have also been found outside the lens at a fraction of their level in the lens (16 specific crystallins are very closely related or identical to metabolic enzymes; they are generally expressed outside the lens and often retain enzymatic activity (30).…”

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confidence: 99%

Xenopus gamma-crystallin gene expression: evidence that the gamma-crystallin gene family is transcribed in lens and nonlens tissues.

et al. 1994

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“…However, it seems likely that they also have roles beyond that of passive ''filler.'' Although mammalian ␥-crystallins may be truly lens-specific, some ␤-crystallins are expressed at lower levels in several non-lens tissues (33,34). A relative of the ␤-and ␥-crystallins, EDSP͞ep37 of Cynops (14), is expressed in differentiating epidermis and shows an intracellular localization consistent with an association with cytoskeleton and a possible role in cell morphology (13,15).…”

Section: Discussionmentioning

confidence: 99%

AIM1 , a novel non-lens member of the βγ-crystallin superfamily, is associated with the control of tumorigenicity in human malignant melanoma

Ray

Wistow

et al. 1997

Proc. Natl. Acad. Sci. U.S.A.

140

119

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AIM1 is a novel gene whose expression is associated with the experimental reversal of tumorigenicity of human malignant melanoma. The predicted protein product of the major 4.1-kb transcript shows striking similarity to the ␤␥-crystallin superfamily. All known members of this superfamily contain two or four characteristic motifs arranged as one or two symmetrical domains. AIM1, in contrast, contains 12 ␤␥ motifs, suggesting a 6-domain structure resembling a trimer of ␤-or ␥-crystallin subunits. The structure of the AIM1 gene shows remarkable similarity to ␤-crystallin genes, with homologous introns delineating equivalent protein structural units. AIM1 is the first mammalian member of the ␤␥ superfamily with a primarily non-lens role. Other parts of the predicted AIM1 protein sequence have weak similarity with filament or actin-binding proteins. AIM1 is a good candidate for the putative suppressor of malignant melanoma on chromosome 6, possibly exerting its effects through interactions with the cytoskeleton. AIM1 (absent in melanoma) is a novel gene whose expression is altered in association with tumor suppression in a model of human melanoma (1). The AIM1 gene is localized to 6q21, within the putative chromosome 6 tumor suppressor region for human melanoma (2). Characterization of the AIM1 gene and its major transcripts reveals, unexpectedly, that AIM1 belongs to the ␤␥-crystallin (␤␥) superfamily.The optical properties of the eye lens largely depend on abundant soluble structural proteins, the crystallins (3-5). Although some crystallins are enzymes, the result of relatively recent gene recruitment events in distinct evolutionary lineages, other crystallins, related to stress-inducible proteins, have more ancient origins and are represented ubiquitously in all vertebrates (6, 7). This ubiquitous class includes the ␤-and ␥-crystallins, which are closely related in sequence and in gene and protein structure (8).Three non-lens members of the ␤␥ superfamily have been identified through a conserved sequence signature: Protein S of Myxococcus xanthus, a sporulating bacterium (9, 10); spherulin 3a of the slime mold Physarum polycephalum (11,12); and an epidermis differentiation-specific protein (EDSP or ep37) of the amphibian Cynops pyrrhogaster (13-15).The structure of Protein S has been confirmed by NMR analysis (16). The structure of a yeast killer toxin (WmKT) has also revealed unexpected similarity to the folding pattern of the ␤␥ superfamily (17). Although an ancestral relationship has been discussed, WmKT may represent an interesting example of evolutionary convergence.Except for spherulin 3a, and possibly WmKT, with two motifs, all other identified members of the ␤␥ superfamily have a 4-fold repeat of the characteristic ␤␥ motif. In contrast, AIM1 contains 12 ␤␥ motifs. Furthermore, the exon͞intron structure of the AIM1 gene shows remarkable similarity with ␤-crystallin genes, with each motif coded by a separate exon.Protein S, a calcium-binding protein of the bacterial spore coat, and spherulin 3a, a ...

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“…Alpha B crystallin was the first one to be found in non-lens tissues [Bhat and Nagineni, 1989;Dubin et al, 1989] and later proved to be functional chaperones that protect other proteins against thermal insults [Horwitz, 1992;Merck et al, 1993]. Members of the bg-crystallins have also been detected outside of lens [Head et al, 1991[Head et al, , 1995Jones et al, 1999;Magabo et al, 2000]. Increased expressions of crystallins have been suggested as a cellular response mechanism against stress [Kamradt et al, 2001[Kamradt et al, , 2002[Kamradt et al, , 2005Whiston et al, 2008;Yaung et al, 2008].…”

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confidence: 95%

Up‐regulation of crystallins is involved in the neuroprotective effect of wolfberry on survival of retinal ganglion cells in rat ocular hypertension model

Chiu

Zhou

Yeung

et al. 2010

J of Cellular Biochemistry

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Wolfberry (fruit of Lycium barbarum Linn) has been known for balancing 'Yin' and 'Yang' in the body, nourishing the liver and kidney, improving visual acuity for more than 2,500 years in oriental countries. The active components in wolfberry include L. barbarum polysaccharide (LBP), zeaxanthine, betaine, cerebroside and trace amounts of zinc, iron, and copper. Each of them confers distinct beneficial effects and together they help to explain widespread use of wolfberry in the eastern world. Earlier study reported the neuroprotective effects of LBP on retinal ganglion cell (RGC) in an experimental model of glaucoma and the underlying in vivo cellular mechanisms of LBP neuroprotection deserve further exploration. In this study, we adopted proteomics, functional genomics, to evaluate pharmacological effects of LBP on the neuronal survival pathways. Among the significantly changed proteins induced by LBP feeding on ocular hypertension (OH) retinas, only proteins in crystallin family were focused in this study. The proteomic results were further confirmed using the Western blotting of the retinas and immunohistochemical staining of the retinal sections. We demonstrated that neuroprotective effect of-wolfberry extract-LBP on the survival of RGCs may be mediated via direct up-regulation of neuronal survival signal betaB2-crystallin.

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Evidence for the extralenticular expression of members of the β-crystallin gene family in the chick and a comparison with δ-crystallin during differentiation and transdifferentiation

Cited by 54 publications

References 59 publications

Xenopus gamma-crystallin gene expression: evidence that the gamma-crystallin gene family is transcribed in lens and nonlens tissues.

Xenopus gamma-crystallin gene expression: evidence that the gamma-crystallin gene family is transcribed in lens and nonlens tissues.

AIM1 , a novel non-lens member of the βγ-crystallin superfamily, is associated with the control of tumorigenicity in human malignant melanoma

Up‐regulation of crystallins is involved in the neuroprotective effect of wolfberry on survival of retinal ganglion cells in rat ocular hypertension model

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