EurekaMag.com logo
+ Site Statistics
References:
53,214,146
Abstracts:
29,074,682
+ Search Articles
+ Subscribe to Site Feeds
EurekaMag Most Shared ContentMost Shared
EurekaMag PDF Full Text ContentPDF Full Text
+ PDF Full Text
Request PDF Full TextRequest PDF Full Text
+ Follow Us
Follow on FacebookFollow on Facebook
Follow on TwitterFollow on Twitter
Follow on Google+Follow on Google+
Follow on LinkedInFollow on LinkedIn

+ Translate

Balbiani ring 1 gene in Chironomus tentans. Sequence organization and dynamics of a coding minisatellite






Journal of Molecular Biology, 2252: 349-361

Balbiani ring 1 gene in Chironomus tentans. Sequence organization and dynamics of a coding minisatellite

Balbiani ring (BR) genes in diptera encode large secretory proteins and are classical model systems for studies of gene expression. In Chironomus tentans, four closely related BR genes, BR 1, BR 2.1, BR 2.2 and BR 6 form a gene family. The BR genes have been partially characterized and are known to contain long arrays of tandemly arranged repeat units with an hierarchical repeat organization. Here, we report the sequence organization of the complete transcribed part of the BR 1 gene in C. tentans. The gene contains five exons and four introns. Three of the introns are located at the 5' end and the fourth at the 3' end of the gene. Exon 4 is approximately 35,000 bases long and is built completely from tandemly organized repeats. We show that this long repeat block contains two types of related repeat units, beta and gamma. Each type forms a large uninterrupted array, a 5' beta array and a 3' gamma array with a sharp border between them. In the hierarchical repeat structure in each repeat array, all repeats are virtually identical at one level of repetition, but shown differences at the next level. The whole repeat block in the BR 1 gene fluctuates in size between different alleles, but not by more than 10%. In contrast, within the block, the beta and gamma arrays vary in length between 8000 and 29,000 bases in an inverse fashion, together keeping the overall length requirement. We propose that the length of exon 4 is conserved by selection of cross-over products of a given length, and that the internal hierarchical sequence organization in the BR 1 gene is a consequence of the combined action of several different sequence turnover mechanisms, all dependent on the unequal pairing of homologous sequences at different, competing levels of repetition.

Accession: 002308108

PMID: 1593624

DOI: 10.1016/0022-2836(92)90926-b

Download PDF Full Text: Balbiani ring 1 gene in Chironomus tentans. Sequence organization and dynamics of a coding minisatellite



Related references

Sequence organization of the Balbiani ring 2.1 gene in Chironomus tentans. Proceedings of the National Academy of Sciences of the United States of America 89(10): 4578-4582, 1992

The Chironomus tentans genome sequence and the organization of the Balbiani ring genes. Bmc Genomics 15(): 819-819, 2015

Evidence for a common ancestor sequence for the Balbiani ring 1 and Balbiani ring 2 genes in Chironomus tentans. Proceedings of the National Academy of Sciences of the United States of America 79(22): 6956-6960, 1982

Balbiani ring 6 gene in Chironomus tentans: a diverged member of the Balbiani ring gene family. Cell 36(4): 1027-1034, 1984

Identification of divergent homologs of Chironomus tentans sp185 and its Balbiani ring 3 gene in Australasian species of Chironomus and Keifferulus. Insect Biochemistry and Molecular Biology. May; 265: 465-473, 1996

A variant tandemly repeated nucleotide sequence in Balbiani ring 2 of Chironomus tentans. Cell 33(2): 555-562, 1983

Characterization of a cloned, moderately repeated sequence from Balbiani ring 2 in Chironomus tentans. Gene 22(1): 85-93, 1983

Developmentally regulated expression of a balbiani ring 1 gene in chironomus tentans. Journal of Cell Biology 103(5 PART 2): 501A, 1986

Repeated nucleotide sequence arrays in Balbiani ring 1 of Chironomus tentans contain internally nonrepeating and subrepeating elements. Journal of Biological Chemistry 258(12): 7793-7799, 1983

A hierarchic arrangement of the repetitive sequences in the Balbiani ring 2 gene of Chironomus tentans. Cell 30(2): 579-587, 1982