Chironomus salivary glands contain a family of high Mr (approximately 1,000 X 10(3)) secretion polypeptides thought to consist of three components: sp-Ia, sp-Ib, and sp-Ic. The use of a new extraction protocol revealed a novel high Mr component, sp-Id. Results of a survey of individual salivary glands indicated that sp-Id was widespread in more than a dozen strains of C. tentans and C. pallidivittatus. Sp-Id was phosphorylated at Ser residues, and a comparison of cyanogen bromide and tryptic peptide maps of 32P-labeled polypeptides suggested that sp-Ia, sp-Ib, and sp-Id are comprised of similar but nonidentical tandemly repeated amino acid sequences. We concluded that sp-Id is encoded by an mRNA whose size and nucleotide sequence organization are similar to Balbiani ring (BR) mRNAs that code for the other sp-I components. Furthermore, parallel repression of sp-Ib and sp-Id synthesis by galactose led us to hypothesize that both of their genes exist within Balbiani ring 2.
Article| September 01 1985
A novel giant secretion polypeptide in Chironomus salivary glands: implications for another Balbiani ring gene.
W Y Kao
S T Case
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1985) 101 (3): 1044–1051.
W Y Kao, S T Case; A novel giant secretion polypeptide in Chironomus salivary glands: implications for another Balbiani ring gene.. J Cell Biol 1 September 1985; 101 (3): 1044–1051. doi: https://doi.org/10.1083/jcb.101.3.1044
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