Multiple genes coding for the frog eye lens γ-crystallins

Tomarev, Stanislav I.; Zinovieva, R. D.; Chalovka, P.; Krayev, A.S.; Skryabin, K. G.; Gause, G.G.

doi:10.1016/0378-1119(84)90074-x

Cited by 35 publications

(12 citation statements)

References 13 publications

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“…Sequence analyses conducted on these genes or their corresponding RNAs have revealed that each gene encodes a highly homologous yet distinct polypeptide of 174 or 175 residues (4,13,27). Similar conclusions have been derived by analysis of y-crystallin cDNAs specific for calves (3) and frogs (31).…”

supporting

confidence: 57%

“…The -y-crystallins, to which the present study is addressed, are encoded in a multigene family (13,27,28,31) whose expression is correlated with differentiation of the lens fiber cells (16,20,21), the predominant cell type of the lens. The -y-crystallins are also of interest because reduced amounts of these proteins have been observed in various forms of cataract (9).…”

mentioning

confidence: 99%

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Structural and evolutionary relationships among five members of the human gamma-crystallin gene family.

Meakin¹,

Breitman²,

Tsui³

1985

Mol. Cell. Biol.

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We have characterized five human y-crystallin genes isolated from a genomic phage library. DNA sequencing of four of the genes revealed that two of them predict polypeptides of 174 residues showing 71% homology in their amino acid sequence; the other two correspond to closely related pseudogenes which contain the same in-frame termination codon at identical positions in the coding sequence. Two of the genes and one of the pseudogenes are oriented in a head-to-tail fashion clustered within 22.5 kilobases. All three contain a TATA box 60 to 80 base pairs upstream of the initiation codon and a highly conserved segment of 44 base pairs in length immediately preceding the TATA box. The two genes and the two pseudogenes are similar in structure: each contains a small 5' exon encoding three amino acids followed by two larger exons that correspond exactly to the two similar structural domains of the polypeptide. The first intron varies from 100 to 110 base pairs, and the second intron ranges from 1 to several kilobases, rendering an overall gene size of 1.7 to 4.5 kilobases. At least one of the two pseudogenes appears to have been functional before inactivation, suggesting that their identical mutation was generated by gene conversion.Transparency of vertebrate eye lenses is generally believed to be a function of the regular arrangement of the lens fiber cells and the high concentration and organization of their major structural proteins, the crystallins. In mammals, these lens-specific proteins have been grouped into three immunologically separate classes, a, 1B, and y, each of which is encoded in a unique gene family (22). The crystallins of each class are expressed at a precise stage of lens development (16, 21) and are highly conserved in evolution (6). Recent studies from this

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supporting

confidence: 57%

mentioning

confidence: 99%

Structural and evolutionary relationships among five members of the human gamma-crystallin gene family.

Meakin¹,

Breitman²,

Tsui³

1985

Mol. Cell. Biol.

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“…They were found to consist of 534 nucleotides, which covers a full-length protein of 177 amino acids including the initiating methionine plus the stop codon. It is worth noting that the frog 3'-crystallin sequences determined here possess the same number of amino acid residues as that of carp TM1 (Chang et al, 1988), whereas the reported sequences from the other Rana frog (Tomarev et al, 1982(Tomarev et al, , 1984 contain only about 168 and 136 residues, indicating that they are incomplete sequences lacking the amino-terminal segments plus some deletions in other parts of the protein chains. From the deduced protein sequences, the isoelectric points (pI) of these two 3'-crystallins were calculated to be 6.364 and 6.366, corresponding to the acidic species shown in Fig.…”

Section: Cdna Amplification By Pcr and Sequence Determinationmentioning

confidence: 93%

“…The gaps were introduced for optimal alignment and maximum homology among the sequences. Note that the sequence of Rana temporaria `/2-crystallin (Tomarev et aL, 1984) lacks an N-terminal segment of five amino acids and bovine/~Bp-crystallin shows greater sequence variation than those y-crystallins themselves, even though they are supposed to belong to a 13/`/superfamily based on three-dimensional structures. The sequences compared here were taken from published sequences of R. temporaria (Tomarev et al 1984), Xenopus ,/1 (Smolich et al, 1993, shark `/M]_I (Chuang, 1994), carp `/M1 (Chang et al, 1988(Chang et al, , 1991, bovine VII (Hay et al, 1987), human 3'5 (Meakin et al, 1985(Meakin et al, , 1987, and bovine /3Bp (Driessen et al, 1981).…”

Section: Structural Comparison Of 7-crystallins Among Various Vertebrmentioning

confidence: 99%

Characterization of γ-crystallin from the eye lens of bullfrog: Complexity of γ-crystallin multigene family as revealed by sequence comparison among different amphibian species

Pan

Chiou

1996

J Protein Chem

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gamma-Crystallin is the major and most abundant lens protein present in the eye lens of lower vertebrates such as amphibian and piscine species. To facilitate structural characterization of gamma-crystallins isolated from the lens of the bullfrog (Rana catesbeiana), a cDNA mixture was synthesized from the poly(A)+mRNA isolated from fresh eye lenses. cDNA encoding gamma-crystallin was then amplified using polymerase chain reaction (PCR) based on two primers designed according to the relatively conserved N- and C-terminal sequences of known gamma-crystallins from teleostean fishes. PCR-amplified product corresponding to gamma-crystallin isoforms was obtained, which was then subcloned in pUC18 vector and transformed into Escherichia coli strain JM109. Plasmids containing amplified gamma-crystallin cDNAs were purified and prepared for nucleotide sequencing by the dideoxynucleotide chain-termination method. Sequencing several clones containing DNA inserts of about 0.54 kb revealed the presence of two isoforms with an open reading frame of 534 base pairs, covering two gamma-crystallins each with a deduced protein sequence of 177 amino acids including the translation-initiating methionine. These gamma-crystallins of pI 6.364 and 6.366 contain a low-methionine content of 2.81%, in contrast to 11-16% obtained for those gamma-crystallins with high-methionine content from most teleostean lenses. Pairwise sequence comparison of bullfrog gamma-crystallins with those published sequences of gamma-crystallins from carp, shark, Xenopus and another Rana frog, bovine, and human lenses indicates that there is only 46-63% sequence similarity among these species, revealing that amphibians possess a very complex and heterogeneous group of gamma-crystallins even from closely related species of Rana frogs. The sequence analysis and comparison of various isoforms of the frog gamma-crystallin family provide a firm basis for identifying these lens proteins as members of a multigene family more complex than that reported for mammalian gamma-crystallins.

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“…Allerdings ist es noch nicht moglich, aus diesen Daten AufschluQ iiber die tatsachliche Anzahl der y-Kristallin-Gene zu erhalten [18]. 8 [19,20], die etwa 650 Nucleotide umfassen und sich in ihrem Muster fur Restriktionsenzyme unterscheiden. Zwei Klone konnten vollstandig sequenziert werden und zeigen 69% Homologie untereinander.…”

Section: B) Molekulargenetik Der Y-kristallineunclassified

Kristalline: Strukturproteine der Augenlinse

Graw

1985

Biologie in unserer Zeit

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Multiple genes coding for the frog eye lens γ-crystallins

Cited by 35 publications

References 13 publications

Structural and evolutionary relationships among five members of the human gamma-crystallin gene family.

Structural and evolutionary relationships among five members of the human gamma-crystallin gene family.

Characterization of γ-crystallin from the eye lens of bullfrog: Complexity of γ-crystallin multigene family as revealed by sequence comparison among different amphibian species

Kristalline: Strukturproteine der Augenlinse

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