Karch, F. | Search bioRxiv

bioRxiv2021

Repression of the Hox gene abd-A by ELAV-mediated Transcriptional Interference

Intergenic transcription is a common feature of eukaryotic genomes and performs important and diverse cellular functions. Here, we investigate the iab-8 ncRNA from the Drosophila Bithorax Complex and show that this RNA is able to repress the transcription of genes located at its 3 end by a sequence-independent, transcriptional interference mechanism. Although this RNA is expressed in the early epidermis and CNS, we find that its repressive activity is limited to the CNS, where in wild-type embryos, it acts on the Hox gene, abd-A located immediately downstream of it. The CNS specificity is achieved through a 3 extension of the transcript, mediated by the neuronal-specific, RNA-binding protein, ELAV. Loss of ELAV activity eliminates the 3 extension and results in the ectopic activation of abd-A. Thus, a tissue-specific change in the length of a ncRNA is used to generate a precise pattern of gene expression in a higher eukaryote.

genetics↗

bioRxiv2018

Rab-mediated trafficking in the secondary cells of Drosophila male accessory glands and its role in fecundity

It is known that the male seminal fluid contains factors that affect female post-mating behavior and physiology. In Drosophila, most of these factors are secreted by the two epithelial cell types that make up the male accessory gland: the main and secondary cells. Although secondary cells represent only 4% of the cells of the accessory gland, their contribution to the male seminal fluid is essential for sustaining the female post-mating response. To better understand the function of the secondary cells, here we investigate their molecular organization, particularly with respect to the intracellular membrane transport machinery. We determined that large vacuole-like structures found in the secondary cells are trafficking hubs labeled by Rab6, 7, 11 and 19. Furthermore, these cell-specific organelles are essential for the long-term post-mating behavior of females and that their formation is directly dependent upon Rab6. Our discovery adds to our understanding of Rab proteins function in secretory cells. We have created an online, open-access imaging resource as a valuable tool for the intracellular membrane and protein traffic community.

cell biology↗