Abstract
Vitellogenin receptors (VgRs) play critical roles in egg formation by transporting vitellogenin (Vg) into oocytes in insects. Although the function of VgR in insects is well studied, the transcriptional regulation of this gene is still unclear. Here, we cloned the promoter of the VgR gene from Bombyx mori (BmVgR), and predicted many POU cis-response elements (CREs) in its promoter. Electrophoretic mobility shift and chromatin immunoprecipitation assays showed that the POU transcription factor POU-M2 bound directly to the CREs of the promoter. Overexpression of POU-M2 in an ovarian cell line (BmNs) enhanced BmVgR transcription and promoter activity detected by quantitative reverse transcription PCR and luciferase reporter assays. Analyses of expression patterns indicated that POU-M2 was expressed in ovary at day two of wandering stage initially, followed by BmVgR. RNA interference of POU-M2 significantly reduced the transcription of BmVgR in ovary and egg-laying rate. Our results suggest a novel function for the POU factor in silkworm oogenesis by its involvement in BmVgR regulation and expands the understanding of POU factors in insect VgR expression.
Highlights
Vitellogenin (Vg) is one of the main nutrients for oviparous animals in the embryonic stage [1,2].The vitellogenin receptor (VgR), which is responsible for transferring Vg from the hemolymph to the ovary by endocytosis, provides nutrients for oocyte maturation and ensures embryonic development [3].The modular structure and function of Vitellogenin receptors (VgRs) are conserved and their functions are well studied among oviparous animals, including insects
To investigate the transcriptional regulation of the BmVgR gene, we cloned a 2.5 kb sequence from its upstream regulatory region (Figure 1A). We used this sequence to drive the expression of a firefly luciferase reporter gene (Luc) by a dual luciferase reporter assay (DLR assay) (Figure 1B,C)
We found some elements potentially binding to various homeodomain transcriptional factors: a homeobox transcription factor containing the POU domain, the CUT domain, and the Abd-B group (Supplementary Table S2 and Figure 1E)
Summary
Vitellogenin (Vg) is one of the main nutrients for oviparous animals in the embryonic stage [1,2].The vitellogenin receptor (VgR), which is responsible for transferring Vg from the hemolymph to the ovary by endocytosis, provides nutrients for oocyte maturation and ensures embryonic development [3].The modular structure and function of VgRs are conserved and their functions are well studied among oviparous animals, including insects. Vitellogenin (Vg) is one of the main nutrients for oviparous animals in the embryonic stage [1,2]. The vitellogenin receptor (VgR), which is responsible for transferring Vg from the hemolymph to the ovary by endocytosis, provides nutrients for oocyte maturation and ensures embryonic development [3]. The modular structure and function of VgRs are conserved and their functions are well studied among oviparous animals, including insects. The transcriptional regulation of VgR gene expression has not been well studied. Transcriptional regulation of VgR has been reported in only a few species. In 2004, the juvenile hormone (JH) analogue was reported to upregulate the expression of VgR in Solenopsis invicta in vitro [4]. In 2006, binding motifs for several transcription factors
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
