Identification of a Developmentally Regulated Gene for a 140-kDa Secretory Protein in Salivary Glands of Chironomus tentans Larvae

Developmentally regulated expression of a Balbiani ring 1 gene for a 180-kD secretory polypeptide in Chironomus tentans salivary glands before larval/pupal ecdysis

The expression of a Balbiani ring 1 gene that codes for a salivary gland-specific 180-kD secretory polypeptide (sp180) is regulated developmentally. Immunoblots of salivary gland protein incubated with an affinity-purified nonapeptide-reactive antibody demonstrated that the salivary gland content of sp180 increases as much as 10-fold between stages 8 and 10 of the fourth larval instar. Hybridiz...

Mobility and Intranuclear Dynamics of Single Balbiani Ring mRNP Particles in Living Chironomus tentans Salivary Glands

The salivary glands of the dipteran Chironomus tentans provide an elegant model system for the analysis of specific messenger ribonucleoprotein particles, the Balbiani Ring (BR) mRNP. BR mRNP particles contain long RNA transcripts of roughly 35-40 kb in size which possess a highly repetitive sequence. The diameter of the granular BR mRNP particles is around 50 nm and their geometry was meanwhil...

Large-sized polysomes in Chironomus tentans salivary glands and their relation to Balbiani ring 75S RNA

Polysomes from the salivary glands of Chironomus tentans were investigated to determine whether Balbiani ring 75S RNA is incorporated into polysomal structures, and thus probably acts as messenger RNA. A new extraction technique for obtaining ribonucleoproteins was applied that gives a high yield of polysomes with only moderate degradation of the cytoplasmic, high molecular weight RNA. The poly...

Atrazine induction of cytochrome P450 in Chironomus tentans larvae.

Cytochrome P450-dependent aldrin epoxidation was characterized in third instar larvae of the aquatic midge, Chironomus tentans. Optimal in vitro assay conditions for the epoxidase were pH 7.6 and 31 degrees C. Activity was linear up to 40 min of incubation time and 0.5 mg microsomal protein per incubation. The activity was concentrated in the microsomal fraction of whole body homogenates and wa...

Spread chromosomal nucleoli of Chironomus salivary glands.