Evidence for a transcellular route for vitellogenin transport in the telotrophic ovary of Podisus nigrispinus (Hemiptera: Pentatomidae)

Abstract

Vitellogenin is the main yolk precursor protein in insect oocytes. It is synthesized in the fat body and released into the hemolymph. To reach the oocyte surface, vitellogenin must cross a single layer of follicular epithelium cells. The transport of vitellogenin across the follicular epithelium has been suggested to occur through the enlarged intercellular spaces (patency) by a paracellular route or by endocytosis by follicular cells and release onto oocyte surface in a transcelluar route. In this study, we investigated whether vitellogenin transport in the meroistic telotrophic ovary of Podisus nigrispinus (Hemiptera) occurs via a paracellular or transcellular route. Light and transmission electron microscopies showed that short cell–cell contacts with well-developed occluding septate junctions were present in follicular cells with patency. Immunofluorescence microscopy revealed the presence of vitellogenin receptors in the plasma membrane and of vitellogenin in the cytoplasm of follicular cells. Data suggest that cell–cell contacts serve as a barrier to large vitellogenin molecules and that this protein is transported via a transcellular route of receptor-mediated endocytosis.

Bicaudal C is required for the function of the follicular epithelium during oogenesis in Rhodnius prolixus

“…We propose that transcytosis plays a role in the uptake of yolk precursors into the oocyte. This has been suggested for insects of different orders, such as Carausius morosus (Phamatodea), Podisus nigrispinus (Hemiptera), and Apis mellifera, Melipona quadrifasciata, Mischocyttarus cassununga, and Pachycondyla curvinodis (Hymenoptera) (Assis et al 2019;Dohanik et al 2018;Fausto et al 2005;Giorgi et al 1998;Ronnau et al 2016). Up to now, vitellogenin uptake by the oocyte had exclusively been attributed to the phenomenon of patency (Davey 1981;Huebner and Anderson 1972b;Huebner and Injeyan 1980).…”

Structural and ultrastructural characters of the reproductive tract in females of the mint leaf beetle Chrysolina herbacea (Duftschmid 1825) (Coleoptera: Chrysomelidae)

“…The vitellarium of C. herbacea contains the differentiated oocytes in the mature ovaries including previtellogenic, vitellogenic and choriogenic stages in a linear arrangement, like in other insects (Assis et al., 2019; Boonyoung et al., 2020; Salazar et al., 2017; Świątek & Górkiewicz, 2006). The vitellarium in C. herbacea has 3–4 oocytes, but the vitellarium of R. ferrugineus consists of the follicle with an oocyte (Wan Nurul ‘Ain et al, 2018).…”

“…Follicular cells undergo amazing changes in the morphology from yolk uptaken (patency) and chorion synthesis. In choriogenic oocyte of C. herbacea , the perioocytic space (between oocyte surface and follicular cells) increased in size, eggshell (chorion) synthesis occurred and intercellular spaces of follicular cells narrowed, as like Podisus nigrispinus (Hemiptera: Pentatomidae) (Assis et al., 2019).…”

Morphology of the reproductive tract of females of leaf beetle Chrysomela populi (Chrysomelidae: Coleoptera)

“…The vitellarium of C. populi contains previtellogenic, vitellogenic and choriogenic oocytes in a linear arrangement as in other insects (Świątek and Górkiewicz 2006;Salazar et al 2017;Assis et al 2019;Boonyoung et al 2020). The vitellarium in C. populi has 3-4 oocytes, but the vitellarium of R. ferrugineus has one oocyte (Wan Nurul 'Ain et al 2018).…”

“…The vitellogenic oocyte of C. populi is surrounded by a monolayer cubic follicle epithelium as in A. sanctaecrucis (Boonyoung et al 2020). In chorigenic oocyte of C. populi, the perioocytic space (between oocyte surface and follicular cells) increased in size, eggshell (chorion) synthesis occurred, and intercellular spaces of follicular cells narrowed, like Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae) (Assis et al 2019).…”