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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of m7GMP release from m7GMP-containing mRNA cap sequence m7GpppG by the embryonic chick lens m7GpppN-pyrophosphatase activity on the synthesis of lens proteins was examined in a newly developed homologous translation system derived from 15-day embryonic chick lenses. The synthesis of total lens polypeptides and delta-crystallin polypeptides, the major translation product, was inhibited 84% and 88%, respectively, by 0.5 mM m7GpppG; m7GMP (0.5 mM) inhibited total synthesis by 63% but was 33% less inhibitory toward delta-crystallin synthesis; GpppG and GMP were not inhibitors, m7GpppG inhibited met-tRNAfmet incorporation into 80S initiation complexes.
Mol Biol Rep 1979 Feb 15
PMID:Differential synthesis of lens proteins in the presence of m7G(5')pppG and cleavage product m7GMP in an embryonic chick lens cell lysate. 22 May 21

The sequences of the A chains of the eye lens protein alpha-crystallin from seventeen mammalian species were compared. They showed a generally slow rate of evolution, but with marked variations in different lineages. Most substitutions have occurred in the C-terminal part of the chain, which probably forms part of the surface of the alpha-crystallin aggregate. The ancestral sequence method of Dayhoff revealed interesting indications about the phylogenetic relationships between the eleven mammalian orders that were represented by the investigated species. Most evident was the divergence of marsupial and placental orders. A notable resemblance between the hyrax and elephant sequences was observed, setting them apart from the ungulates, including whale. Primates, rodents, lagomorphs, insectivores and tupaiids seem to derive from a common stem group. These phylogenetic inferences are discussed in relation to current palaeontological and taxonomical opinions, and compared to evidence from other protein sequence data.
J Mol Evol 1977 Nov 25
PMID:Evolutionary changes of alpha-crystallin and the phylogeny of mammalian orders. 59 19

Variations in size and charge of calf lens proteins, particularly gamma crystallins, were studied by polyacrylamide gel electrophoresis. Exposure of gamma crystallins to near-UV light in the presence of L-tryptophan produces species of higher electrophoretic mobility and higher retardation. Treatment with urea and sulfonation also produced changes in the retardation co-efficient. The increase of retardation co-efficient of gamma crystallin is interpreted to be a result of conformational changes. Gamma crystallins are particularly sensitive to photo-modification, and this process may be associated with age-related changes in the lens.
Mol Cell Biochem 1976 Jul 30
PMID:Modification of calf lens crystallins as determined by gel electrophoresis. 96 62

A single, major 21 S messenger ribonucleoprotein (mRNP complex) was isolated and purified by sucrose gradient centrifugation after EDTA treatment of high salt washed polysomes from 15 day embryonic chick lenses. A 17 S mRNA was released from the 21 S subunit of delta crystallin. Similar results were obtained with the 17 S mRNA released from the 21 S mRNP complex.
Mol Biol Rep 1976 Sep
PMID:Synthesis of delta crystallin from embryonic chick lens messenger ribonucleoprotein complex. 103 4

The medaka (Oryzias latipes) is an egg-laying fresh-water fish. We describe the medaka as a model system of transgenic fish in germs of biological characteristics, manipulation of embryos, gene expression in development, and basic research in aquaculture. The fish are small (approximately 3 cm in length) and have a short generation time (approximately 3 months). The eggs are easy to manipulate. A foreign gene (e.g., the chicken delta crystallin gene) is transferred and expressed stage-dependently in development of medaka embryos. Growth hormone genes of vertebrates are transferred and expressed and, in some cases, accelerate growth of the fish. Thus, the medaka is one of the most promising models of transgenic fish for basic research of gene expression and aquaculture.
Mol Mar Biol Biotechnol
PMID:Medaka as a model of transgenic fish. 130 24

Many of the structural proteins of ocular lenses, commonly referred to as crystallins, are identical to specific enzymes or the result of a recent gene duplication (Piatigorsky, J., and Wistow, G. (1991) Science 252, 1078-1079). One such enzyme, aldehyde dehydrogenase (ALDH), has been recruited as a lens crystallin in certain mammals (Wistow, G., and Kim, H. (1991) J. Mol. Evol. 32, 262-269) and cephalopods (Tomarev, S., Zinovieva, R., and Piatigorsky, J. (1991) J. Biol. Chem. 266, 24226-24231). We report here that a transparent tissue, derived from muscle but functioning as a lens in the light-emitting organ of a squid, Euprymna scolopes, shows striking biochemical convergence with the epidermally derived ocular lenses of some mammals and cephalopods. In the light organ lens of E. scolopes, an ALDH-like protein is the predominant molecular component. The typical muscle-specific proteins are replaced as the dominant species by a protein composed of 54-kDa subunits. This protein, which we designate as L-crystallin, constitutes approximately 70% of the total soluble protein of the light organ lens. The amino acid sequences of three peptides of L-crystallin (approximately 9% of the total protein) showed 54.5% sequence identity with human cytosolic ALDH. Using polyclonal antiserum made against L-crystallin, we found that it is present in low abundance in other tissues of the squid, including muscle and the ocular lens. This polyclonal antiserum also cross-reacted with the ALDH-like crystallins found in the ocular lenses of certain mammals and cephalopods. L-Crystallin showed no ALDH activity, which is similar to several other enzyme/crystallins, including ALDH/eta-crystallin (Wistow, G., and Kim, H. (1991) J. Mol. Evol. 32, 262-269). The characteristics of this muscle-derived lens are evidence that a common biochemical basis underlies transparency and that certain proteins may possess properties that promote their selection as lens structural proteins.
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PMID:The muscle-derived lens of a squid bioluminescent organ is biochemically convergent with the ocular lens. Evidence for recruitment of aldehyde dehydrogenase as a predominant structural protein. 140 Apr 15

Previous transfection experiments have shown that 162 base pairs (bp) of the 5' flanking sequence of the chicken alpha A-crystallin gene are required for promoter activity in primary chicken lens epithelial cells (PLE), while only 111 bp of the 5' flanking sequence are needed for activity of the mouse alpha A-crystallin promoter in transfected chicken PLE cells or in a SV40 T-antigen-transformed transfected mouse lens epithelial cell line (alpha TN4-1). The effect of site-directed mutations covering positions -111 to -34 of the mouse alpha A-crystallin promoter fused to the bacterial chloramphenicol acetyltransferase (CAT) gene was compared in transfected chicken PLE cells and mouse alpha TN4-1 cells; selected mutations were also examined in a nontransformed rabbit lens epithelial cell line (N/N1003A). In general, the same mutations reduced promoter activity in the transfected lens cells from all three species, although differences were noted. The mutations severely affected regions -111/-106 and -69/-40 regions in all the transfected cells examined; by contrast, mutations at positions -105/-99 and -87/-70 had a somewhat greater effect in the chicken PLE than the mouse alpha TN4-1 cells, while mutations of the -93/-88 sequence reduced expression in the alpha TN4-1 but not the PLE cells. A partial cDNA with sequence similarity to alpha A-CRYPB1 of the mouse has been isolated from a chicken lens library; mouse alpha A-CRYBP1 is a putative transcription factor which binds to the -66/-55 sequence of the mouse alpha A-crystallin promoter.(ABSTRACT TRUNCATED AT 250 WORDS)
J Mol Evol 1992 Oct
PMID:Conservation of mouse alpha A-crystallin promoter activity in chicken lens epithelial cells. 140 19

Native alpha-crystallin, obtained from the cortex of calf lenses with FPLC (Pharmacia) was characterized by means of transient-electric-birefringence measurements and ultraviolet linear-dichroism spectroscopy. These techniques were also performed on 6-M-urea-dissociated and reconstituted alpha-crystallin. Transient-electric-birefringence measurements offer the possibility to characterize the often observed, but usually neglected, non-spherical occurrences of alpha-crystallin in more detail. Although not distinguishable with size-exclusion chromatography, we could identify at least two different classes of both native and reconstituted alpha-crystallin, from which at least one consists of non-spherical molecules. The results are compared with those obtained with electron microscopy using different staining methods. From the three independent techniques used we find evidence that a fraction of the alpha-crystallin exists in a more extended quaternary structure. The results are difficult to explain with a concentric three-layer model for alpha-crystallin as proposed by Tardieu et al. [Tardieu, A., Laporte, D., Licinio, P., Krop, B. & Delaye, M. (1986) J. Mol. Biol. 192, 711-724].
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PMID:Alpha-crystallin exists in a non-spherical form. A study on the rotational properties of native and reconstituted alpha-crystallin. 144 73

Phylogenetic relationships were examined among 35 alpha-crystallin-related heat-shock proteins from animals, plants, and fungi. Approximately one-third of the aligned amino acids in these proteins were conserved in 74% of the proteins, and three blocks of consensus sequence were identified. Relationships were established by maximum parsimony and distance matrix analyses of the aligned amino acid sequences. The inferred phylogeny trees show the plant proteins clearly divided into three major groups that are unrelated to taxonomy: the chloroplast-localized proteins and two groups that originate from a common ancestral plant protein. The animal proteins, in contrast, branch in accordance with taxonomy, the only clear exception being the alpha-crystallin subgrouping of vertebrates. This analysis indicates that the small heat-shock proteins of animals have diverged more widely than have the plant proteins, one group of which is especially stable.
J Mol Evol 1992 Dec
PMID:Phylogeny of the alpha-crystallin-related heat-shock proteins. 147 6

Plane charge clusters from the calf eye lens protein gamma-crystallin are considered. The clusters consist of four to six side chain charged groups with interatomic distances in ionic pairs from 4 to 7 A. The charge clusters appear to decrease the hydrophilic potential of the molecular surface which maintains the transparent refracting lens medium of vertebrates with a very high protein concentration. It is shown that the charge pattern for different gene products of one species is conservative as well as for whole set of 25 sequences of vertebrates, including carp, frog, mouse, rat, calf and human. Taking into account "neutral mutations", Asp-Glu and Arg-Lys the homology of those charge positions is equal to 95-100%. Functionally important charge clusters are absent in the ancient structural motifs of gamma-crystallin.
Mol Biol (Mosk)
PMID:[Planar charged clusters--structural invariants of the gamma-crystallin family of the crystalline lens: functional role and evolutionary conservatism]. 149 83


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