cDNA clones for the ecdysone-inducible polypeptide (EIP) mRNAs of Drosophila Kc cells

Abstract

The ecdysone‐inducible polypeptides (EIPs) 28, 29 and 40 were identified previously as polypeptides whose synthesis is stimulated early in the ecdysone response of Drosophila Kc cells. We have now shown, using two‐dimensional gels, that each of these EIPs consists of three species differing in pI, and all stimulated by ecdysone. Translations and hybrid‐arrested translations indicated that the poly(A)+ EIP mRNAs increase ˜10‐fold in abundance during the first 4 h of ecdysone treatment. By a differential screen of a cDNA library we have identified cDNA clones corresponding to all three EIPs. Two kinds of clones were isolated: one hybridizes to the EIP 40 mRNA(s); the second hybridizes to the mRNA(s) encoding all the EIPs 28 and 29. The EIP 28/29 and EIP 40 loci detected by these clones are each present at single sites on the polytene chromosomes and each is at or in the vicinity of an ecdysone‐regulated puff.

Identification of ecdysone response elements by analysis of the Drosophila Eip28/29 gene.

“…Our goal has been to identify ecdysone-response elements (EcREs); to do so we have begun by identifying sequences necessary for the hormonal regulation of the gene Eip28/29, which is ecdysone-inducible in some Diosophila cell lines (Savakis et al 1980(Savakis et al , 1984 and in some larval tissues (Andres 1990). In cell lines this induction is known to be transcriptional and rapid (Savakis et al 1980(Savakis et al , 1984Bieber 1986); in these respects, its regulation can be considered analogous to that of the "early puffs" in the salivary gland.…”

“…In cell lines this induction is known to be transcriptional and rapid (Savakis et al 1980(Savakis et al , 1984Bieber 1986); in these respects, its regulation can be considered analogous to that of the "early puffs" in the salivary gland. The region just upstream of Eip28/29 is transcriptionally complex; the genes z600, gdl, and Eip28/29 are represented by overlapping transcription units on a single DNA strand, but the three genes are expressed at very different times and places in development Schulz and Butler 1989;Schulz and Miksch 1989).…”

Alternative splicing generates two distinct Eip28/29 gene transcripts in Drosophila Kc cells.

“…The Eip28/29 gene is one of the genes encoding a small set of ecdysoneinducible polypeptides (EIPs), which are distinguished by their rapid induction in some Drosophila cell lines following ecdysone treatment (2,3 4. It extends 2146 nucleotides (nt), includes three introns, and gives rise to a predominant mature transcript of 979 nt, which, with poly(A) added, migrates as a diffuse band of about 1200 nt (R.A.S., unpublished data).…”

“…It extends 2146 nucleotides (nt), includes three introns, and gives rise to a predominant mature transcript of 979 nt, which, with poly(A) added, migrates as a diffuse band of about 1200 nt (R.A.S., unpublished data). This transcript accumulates rapidly following hormone addition, increasing 5-to 15-fold and becoming about 1% of the poly(A)+ RNA by the end of 3 hr (4,5). This induction is due to an earlier rapid increase in the synthesis of Eip28/29 gene transcripts; the transcriptional increase is detectable within 10 min and is half completed in about 30 min (5).…”

“…The polypeptide products of these transcripts have been described (4). These include at least six forms of EIPs 28 and 29.…”