The repetition frequency of DNA in Balbiani ring 2 of Chironomus thummi

Wobus, Ulrich; Serfling, Edgar

doi:10.1007/bf00328082

Cited by 15 publications

(3 citation statements)

References 19 publications

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“…Whereas each BR gene is present in probably only one copy per genome, BR DNA appears to be highly repetitive (6)(7)(8)(9). This paradox is explained by the fact that BR genes contain internal repeats.…”

Section: Introductionmentioning

confidence: 99%

The basic repeat unit of aChironomusBalbiani ring gene

Bäumlein¹,

Wobus²,

Gerbi

et al. 1982

Nucl Acids Res

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A clone derived from the Balbiani ring b (BRb) gene of Chironomus thummi has been used to study the internal organization of that gene. Much of the gene consists of approximately 80 copies of a ca. 300 bp repeat unit, which are tandemly organized. The BRb clone contains a major part of that unit (242 bp). Sequence analysis shows that approximately 60% of the unit corresponds to short, tandemly organized subsequences, which encode peptides 8 to 11 residues long. In turn, each subsequence consists of even shorter internal repeats, corresponding to a tripeptide (consensus Proline. Serine. Lysine.). The remainder of the ca. 300 bp unit probably does not have obvious repetitive substructure.

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Section: Introductionmentioning

confidence: 99%

The basic repeat unit of aChironomusBalbiani ring gene

Bäumlein¹,

Wobus²,

Gerbi

et al. 1982

Nucl Acids Res

Self Cite

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“…secretory polypeptides (Grossbach, 1977;Rydlander et al, 1980) which are spun into the elastic threads that make up the protective tube and food-gathering funnel of the aquatic midge larva. Although the genes are probably single-copy, their DNAs behave as middle-repetitive elements, because they contain internal repeats (Lambert, 1972;Wobus and Serfling, 1977;Wieslander, 1979). We have previously reported the isolation and partial characterization of a recombinant DNA clone, pCthBRc-19, which is derived from the BRc gene of C. thummi (Wobus et al, 1980).…”

Section: Introductionmentioning

confidence: 99%

Characterization of a 249-bp tandemly repetitive, satellite-like repeat in the translated portion of Balbiani ring c of Chironomus thummi.

Bäumlein¹,

Wobus²,

Gerbi³

et al. 1982

The EMBO Journal

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A major part of Balbiani ring (BR)c DNA of Chironomus thummi consists of tandem 249‐bp repeats which appear to be transcribed and translated into a polypeptide of very unusual composition. Whereas these 2549‐bp repeats are evident by Southern blotting, sequence analysis reveals a finer tandemly repetitive substructure: more than half of the 249‐bp repeat length consists of tandem 24‐bp subrepeats, and these in turn may have been generated from even shorter sequences. Comparisons with partial BRb and BR1 sequences reveal that this hierarchically repetitive sequence structure is typical of BR genes. It resembles the structure of some satellite sequences, suggesting that mechanisms leading to satellite DNA evolution may also operate in the evolution of structural genes.

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“…Each BR gene is present in one or a few copies per genome and contains internally repeated DNA (Lambert, 1972;Wobus and Serfling, 1977;Wieslander, 1979 cloning of BRI sequences of C. tentans and the possible BR2 homologue in C. thummi (BRc), revealed tandemly-repeated sequences within BR DNA (Degelmann and Hollenberg, 1981;Wobus et al, 1980). We have studied genomic clones from BR2 of C. pallidivittatus which is closely related to C. tentans as shown by the formation of fertile hybrids.…”

Section: Introductionmentioning

confidence: 99%

Constant and variable parts in the Balbiani ring 2 repeat unit and the translation termination region

et al. 1982

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The large Balbiani rings of the chironomids produce giant internally repeated transcripts that are translated into silk‐like proteins used for protective tubes. We have cloned fragments of the Balbiani ring 2 (BR2) gene of Chironomus pallidivittatus, normally the most prominent BR, for sequencing and restriction analysis. The results indicate a basic, tandemly arranged repeat unit of 198 bp, consisting of an invariant region of 102 bp followed by a variable region of 96 bp, the latter containing short internal tandem repeats. In the coding strand of both regions, there is a tendency to maximize adenine (˜40%) and minimize cytosine + thymidine (32‐33%). Stringency in codon usage and absence of preference for third position nucleotide substitutions between homologous sequences suggest selection at the nucleotide level to be important. Both regions code for peptides rich in basic amino acids, but show distinct differences in other coding properties. The invariant region probably codes for a crystalline domain, and the variable region for a proline‐rich, amorphous domain. One of the clones includes the 3′ end of the translated region. Surrounding and following two stop codons is a sequence of four short palindromes. Furthermore, the first stop codon is part of a sequence reminiscent of a “TATA box”. The possibilities are discussed that this area of the gene might be a target for regulatory molecules controlling translation termination and/or the expression of an overlapping cistron.

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The repetition frequency of DNA in Balbiani ring 2 of Chironomus thummi

Cited by 15 publications

References 19 publications

The basic repeat unit of aChironomusBalbiani ring gene

The basic repeat unit of aChironomusBalbiani ring gene

Characterization of a 249-bp tandemly repetitive, satellite-like repeat in the translated portion of Balbiani ring c of Chironomus thummi.

Constant and variable parts in the Balbiani ring 2 repeat unit and the translation termination region

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