Comparative and Evolutionary Aspects of delta-Crystallin in the Vertebrate Lens

Williams, Leah A.; Piatigorsky, Joram

doi:10.1111/j.1432-1033.1979.tb04177.x

Cited by 50 publications

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References 36 publications

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“…The crystallins, or structural proteins within the lens, comprise as much as 90% of the soluble protein of the lens. There are four families of crystallins (a-, f3, y, and 8-crystallin), with 6-crystallin being confined to birds and reptiles (1,2). Reviews on lens differentiation and lens crystallins can be found elsewhere (3-6).…”

Section: Introductionmentioning

confidence: 99%

Direct observation of delta-crystallin accumulation by laser light-scattering spectroscopy in the chicken embryo lens.

Sun¹,

Tanaka²,

Nishio³

et al. 1984

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

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By using the technique of laser light-scattering spectroscopy, direct observation has been made on the intracellular accumulation of a crystallin protein within the cells of chicken embryo lens during the process of development. Appearance of 8-crystallin has been detected as early as day 4, and its concentration reaches a plateau at day 19. The measurements constitute a noninvasive determination of accumulation of protein molecules that specifically characterize the process of cell differentiation.Rapid progress is being made in the understanding of molecular events of cellular differentiation, particularly at the level of gene expression. Lens cell differentiation has been a favorable system of investigation because it is associated with a marked change in morphology (cell elongation) and differential synthesis of the soluble proteins (crystallins). The crystallins, or structural proteins within the lens, comprise as much as 90% of the soluble protein of the lens. There are four families of crystallins (a-, f3, y, and 8-crystallin), with 6-crystallin being confined to birds and reptiles (1,2). Reviews on lens differentiation and lens crystallins can be found elsewhere (3-6).In the chicken lens, 8-crystallin is the first crystallin to appear (7) and can be detected already at the lens placode stage of development (8, 9). This protein accumulates in the embryonic lens until it comprises 70-80% of the soluble protein in the developing lens fiber cells (10-12). 8-Crystallin synthesis gradually ceases during the first few months after hatching (13)(14)(15). Consequently, the concentration of 8-crystallin is high in the center (nucleus) of the adult lens, which contains cells deposited early in development, and is low or absent at the periphery of the lens (cortex), which contains the cells deposited later in development (16) (Fig. 1) where q = (4ir/X) sin(6/2) is the scattering wave number, X is the wavelength of the laser light in water, 6 is the scattering angle (. = 900 in this experiment), and A and B are constants proportional to the square of concentration and molecular weight of the macromolecules. The diffusion coefficient is further related, via the Stokes-Einstein-Kawasaki-Ferrel formula, to the correlation length, a, of the macromolecules D = kT/6mrra, where k is the Boltzmann constant, T is the absolute temperature, and qj is the viscosity of water. The correlation length a is the average distance beyond which the motion of neighboring macromolecules becomes independent. When interaction is negligible, the correlation length is simply the hydrodynamic radius of the macromolecules.When there are macromolecules of different sizes and, therefore, different diffusion coefficients, the correlation function is given by the superposition of the correlation functions corresponding to each size. By precise analysis of the correlation function, it is, in principle, possible to determine the size distribution and the concentration of the macromolecules. 785The publication costs of this article were defray...

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Section: Introductionmentioning

confidence: 99%

Direct observation of delta-crystallin accumulation by laser light-scattering spectroscopy in the chicken embryo lens.

Sun¹,

Tanaka²,

Nishio³

et al. 1984

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

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“…Comparison of the nucleotide sequences of the 3major-and the f'im~r-globin genes to each other (24) and to the a-globin genes (25) also indicates greater divergence in the flanking and intervening sequences than in the mRNA gene sequences. If the b-crystallin gene(s) arose with the reptiles, as suggested by hybridization experiments with b-crystallin cDNA (14), the gene duplication took place within the last 200-800 million years (26). An alternative explanation is that the two genes for 3-crystallin arose simultaneously.…”

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Interestingly, the ratio of synthesis of the subunits is a function of electrolyte concentrations in the cultured embryonic lens (11) or in a rabbit reticulocyte lysate supplemented with b-crystallin mRNA (12). Finally, 6-crystallin differs evolutionarily from the other lens crystallins in that it is found only in birds and reptiles (13,14).Recently, we have cloned a b-crystallin cDNA (pSCr2), allowing direct examination of b-crystallin sequences in the genome (15). Initial studies utilizing the cloned cDNA as a probe provided evidence that there are at least two 3-crystallin genes containing many intervening sequences in the chicken (16).…”

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confidence: 99%

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Comparison of two delta-crystallin genes in the chicken.

Bhat¹,

Sullivan²,

Piatigorsky³

1980

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

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Restriction endonuclease mapping and electron microscopy established that there are at least two nonalielic 5-crystallin genes in the chicken. The structure of a complete 5-crystallin gene has been deduced by analysis of five cloned fragments from the chicken genome. Fifteen intervening sequences compose approximately 80% of this gene; the other gene contains at least 14 intervening sequences. The mRNA gene sequences appear to be similar; at least 60% divergence was found between the intervening sequences of the two 5-crystallin genes. Insertions or deletions or both appear to be major events responsible for these differences. b-Crystallin, a structural protein of the ocular lens, has several interesting features. First, b-crystallin is a useful marker for studying differential gene expression because it is the first (1-3) and principal (4-6) crystallin synthesized during lens development in the chicken. Second, b-crystallin is a tetrameric protein (7) composed of subunits with molecular weights of 50,000 and 48,000 (8). It is not known whether the two subunits are products of different genes or whether one is posttranslationally derived from the other. The b-crystallin polypeptides are similar (8, 9): only two tryptic peptide differences have been detected between the 50,000 and 48,000 b-crystallin subunits (10). Interestingly, the ratio of synthesis of the subunits is a function of electrolyte concentrations in the cultured embryonic lens (11) or in a rabbit reticulocyte lysate supplemented with b-crystallin mRNA (12). Finally, 6-crystallin differs evolutionarily from the other lens crystallins in that it is found only in birds and reptiles (13,14).Recently, we have cloned a b-crystallin cDNA (pSCr2), allowing direct examination of b-crystallin sequences in the genome (15). Initial studies utilizing the cloned cDNA as a probe provided evidence that there are at least two 3-crystallin genes containing many intervening sequences in the chicken (16). In the present experiments we have examined five cloned fragments containing major portions of the b-crystallin genes by restriction endonuclease mapping and heteroduplex analysis.MATERIALS AND METHODS Preparation of DNA. Fertilized eggs from two lines of inbred White Leghorn chickens were obtained: one was gsnegative, Cofal Marek-negative (Spafas, Lancaster, PA) and one was line 6, subline 3 from the U.S. Department of Agriculture (Lansing, MI). DNA was prepared from pooled embryos of 6-to 12-day-old chickens by homogenizing 1 g of tissue in 10 vol of buffer A (0.1 M sucrose/3 mM CaCl2/3 mM Mg9l2/0.01 M Tris-HCl, pH 8.0/0.1% Triton X-100/0.5 mM dithiothreitol) (17). The homogenate was layered over a cushion of buffer A containing 0.3 M sucrose (without Triton X-100) and centrifuged at 3000 rpm in a Sorvall HB4 rotor. The nuclear pellet was resuspended in 100 vol of 0.01 M Tris-HCl, pH 8.0/0.15 M NaCl/0.01 M Na4EDTA, adjusted to 0.5% in NaDodSO4, and digested with 200 ,ug of proteinase K (Boehringer Mannheim) per ml at 370C for 15 hr. The DNA was then phenol ...

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“…Besides, when we focus on the two representatives, i. e. b-crystallin and feather type keratins, we notice that these proteins are only found in reptiles and birds. Deltacrystallin of reptiles and birds has been shown to have similarities not only in molecular weight, amino acid composition, and partial proteolytic pattern but also in the sequence of the genes (19,20). Similarity between reptilian and avian keratins has long been shown by X-ray diffraction studies (21), and recent biochemical studies suggest that keratins of reptilian scales and claws have similarity to avian scale keratins but not to mammalian keratins (22,23).…”

Section: Existence Of Common Antigenicity Between B-crystallin and Kementioning

confidence: 99%

Characterization of an Antiserum against Feather Keratins of the Chick: Its Crossreaction with a Lens Protein, δ‐crystallin

Kodama

Eguchi

1983

Dev Growth Differ

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We prepared an antiserum against a fraction of solubilized keratins extracted from down feathers of newly hatched chicks. The specificity of the antiserum was tested by double immunodiffusion, immunofluorescent staining, and immunoblotting after sodium dodecylsulfatepolyacrylamide gel electrophoresis. All the bands except "Fast protein" reacted with the antiserum, suggesting the presence of a common antigenicity through various polypeptides in solubilized feather keratins. Delta-crystallin, which is a lens specific protein, also reacted with the antiserum. The presence of a common antigenicity between d-crystallin and feather and scale keratins was confirmed by affinity-purification of the antiserum, and its significance is discussed.The avian feather shows distinct X-ray diffraction pattern from mammalian skin or hair and its constituent proteins, i.e. feather keratins are also distinct from mammalian keratins by their low molecular weight (see review, I). The molecular weight of feather keratins are estimated to be about 1 1 K, while those of mammalian keratins range from 40 K to 65 K (2). Since feather keratins are insoluble in aqueous buffer, reduction and S-carboxymethylation procedure have been adopted to solubilize them and make them applicable to biochemical analyses. Polyacrylamide gel electrophoresis at both acidic and basic pH show that S-carboxymethylated (SCM) feather keratins can be separated to several bands, suggesting the total number of homologous polypeptides to be at least 35 (3). This number coincides well with the estimated number of keratin mRNA in the embryonic chick feather (4). Partial amino acid sequence analysis also confirmed the microheterogeneity of keratin polypeptides (5).We previously reported that limb bud cells of 4-day-old chick embryo can synthesize a lens specific protein, 6-crystallin, when cultured as aggregates, and that those cells containing &crystallin are derived from both the ectoderm and the mesoderm of the limb bud (6). For the further analysis of this phenomenon, a probe for the normal differentiation of limb bud cells was needed. We selected feather keratins, as they are the terminal differentiative products of the ectodermal cells of the limb bud, and raised an antiserum against some of the feather keratin polypeptides. The specificity of the antiserum was checked by the double immunodiffusion test, the indirect immunofluorescent staining and the immunoblotting test. Unexpectedly, the antiserum also reacted with 6-crystallin. Delta-crystallin is not contained in feather at all and further purification of the antiserum showed that there is a group of antibodies * Present address:

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Comparative and Evolutionary Aspects of delta-Crystallin in the Vertebrate Lens

Cited by 50 publications

References 36 publications

Direct observation of delta-crystallin accumulation by laser light-scattering spectroscopy in the chicken embryo lens.

Direct observation of delta-crystallin accumulation by laser light-scattering spectroscopy in the chicken embryo lens.

Comparison of two delta-crystallin genes in the chicken.

Characterization of an Antiserum against Feather Keratins of the Chick: Its Crossreaction with a Lens Protein, δ‐crystallin

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