Cis-regulatory elements affecting the Nanos gene promoter in the germline stem cells

Drosophila Nanos gene plays an important role in stem cell maintenance and body patterning. With the purpose of understanding the cis-regulatory machinery involved in the transcription of the nanos gene in the germline stem cells, we examined its promoter fragment from +97 to −708 relative to the transcription start site and identified enhancer elements located between position −108 and +97. Experiments with transgenic flies revealed that the minimal promoter (from −108 to +20) is sufficient in the germline stem cells for the GFP expression in transgenic Drosophila. Moreover, the flag-tagged nanos protein blotting experiments revealed that a short promoter fragment plus some sequences of the nos 5′ UTR spanning −108 to +97 could efficiently drive the expression of the flag-tagged [Nos-mRNA-nos3′UTR] transgene in transgenic flies indicating that the cis-regulatory elements located between positions −108 and +97 of the nanos promoter are sufficient to fully transcribe the nanos mRNA. Deletion of the identified cis-acting sequences from the promoter rendered it non-functional as it could no longer transcribe the nanos mRNA in transgenic flies thus revealing the importance of these sequences for the transcription of the nanos gene.