Biomedical subjects

E M Jorgensen

Publications and source records attributed to E M Jorgensen.

21 records · Page 2Linked to original sources

PubMed1991

Positive and negative control of the Antennapedia promoter P2.

To understand the nature of the regulatory signals impinging on the second promoter of the Antennapedia gene (Antp P2), analysis of its expression in mutants and in inhibitory drug injected embryos has been carried out. The maternally-active gene osk is identified as one of two general repressors of P2 which prevent Antp transcription until division cycle 14. Products of the zygotically-active segmentation genes ftz, hb, Kr, gt and kni then act as activators or repressors of Antp P2 in a combinatorial fashion. The timing of these events, and their positive versus negative nature, is critical for generating the expression patterns normal for Antp.

Animals↗

PubMed1987

Function and misfunction of the two promoters of the Drosophila Antennapedia gene.

In the Antennapedia (Antp) gene of Drosophila melanogaster, structurally distinct RNAs arise from different transcription initiation sites. When the two sites are separated by a chromosome inversion, transcripts are produced from each fragment of the split Antp locus, and these RNAs initiate at the same nucleotide as in wild-type animals. Thus, the initiation sites are regulated by independent promoters. We show by in situ hybridization that transcripts from each promoter accumulate in spatially distinct patterns in a subset of wild-type imaginal discs. Importantly, these patterns are generally maintained in the inversion mutant. We conclude that the promoters possess independent and dissimilar regulatory elements for spatial activation. Finally, we have looked at transcription in seven different dominant Antp mutants, all of which show a transformation of head tissue to thoracic tissue. In each mutant, the second promoter is improperly activated in the eye-antennal imaginal disc. Because all but one of these mutations have inversion breakpoints distantly upstream of the activated promoter, they probably act via long-range euchromatic position effects. Our studies define how the dual promoters and chromatin structure of the Antp gene contribute to the generation of a complex pattern of transcription.

Animals↗

PubMed1986

Multiple transcripts from the Antennapedia gene of Drosophila melanogaster.

The structures of four major transcripts from the homeotic gene Antennapedia of Drosophila melanogaster were determined. These transcripts constitute two RNA classes, each class initiating from a unique promoter but sharing 3' exons. Within the shared sequences is a major open reading frame encoding a 378-amino-acid protein as well as alternative polyadenylation sites. Although the RNA classes differ in their 5' sequences, both leaders contain many AUGs upstream of the major open reading frame. For the two RNA classes, neither gross tissue nor temporal specificity was observed. However, the second poly(A) site is preferred in neural tissue. The structural diversity of the RNAs is discussed in relation to biological functions of the Antennapedia locus.

Amino Acid Sequence↗