What are Balbiani rings?

Balbiani rings are exceptionally large puffs on the polytene chromosomes in the dipteran Chironomus tentans. These puffs are particularly well suited for studies of the structure of active genes and the synthesis and transport of specific RNA-protein (RNP) particles.

Who discovered Balbiani rings?

The hereditary nature of these structures was not confirmed until they were studied in Drosophila melanogaster in the early 1930s by German biologists Emil Heitz and Hans Bauer. In 1930, Heitz studied different species of Drosophila (D. melanogaster, D. simulans, D.

Which portion of the chromosome is referred to as the Balbiani ring?

Chromosome puffs. Electron micrographs of certain puffs, called Balbiani rings, of Chironomus salivary gland polytene chromosomes show the chromatin arranged in loops (Figures 4-42 and 4-43), much like those observed in the amphibian lampbrush chromosomes discussed earlier.

Who discovered polytene chromosome?

Balbiani
Polytene chromosomes were discovered by Balbiani (1881) in larval salivary glands, Malpighian tubules, intestine, hypoderm and muscles of Chironomus plumosus as a cy- lindrical cord that repeatedly unravelled and filled the nucleus. He called this structure a ‘permanent spireme’.

Where can you find the Balbiani ring gene?

We describe such a system, the Balbiani ring ( BR) genes in polytene cells in the dipteran Chironomus tentans.

Where does the Balbiani ring live under water?

The larvae live under water in a thin fibrous protein tube, a protective and food-gathering funnel, the components of which are continuously produced by the salivary gland cells.

Why are the rings on a puff called Balbiani rings?

The chromonemata of puffs give out a series of many loops laterally. As these loops appear as rings, they are called Balbiani rings after the name of the researcher who discovered them. They are formed of DNA, RNA and a few proteins.

How is the Balbiani ring used in mRNA export?

Their contribution to mRNA export was then validated using fluorescence in situ hybridization (FISH) using oligo-dT probes. In addition, FISH-based screens identified multiple rat (ribonucleic acid trafficking, Amberg, Goldstein, & Cole, 1992) and brr (bad response to refrigeration, de Bruyn Kops & Guthrie, 2001) mutants impaired for mRNA export.

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