Blood vessel/epicardial substance (bves) expression, essential for embryonic development, is down regulated by Grk/EFGR signalling

Abstract

The Pop1/Bves (blood vessel/epicardial substance) gene is a member of the popeye gene family recently identified in various species. It encodes a potential transmembrane glycoprotein and is a cell adhesion molecule present in skeletal and cardiac muscle and epithelia. We isolated the Drosophila homologue of Bves (DmBves) and found, using in situ hybridisation to RNA in ovaries, that bves is expressed in all follicular epithelial cells surrounding the oocyte at stage 10, except those in very posterior and anterior-dorsal regions adjacent to the oocyte. We show that the repression of bves expression in anterior-dorsal follicle cells is regulated by the Grk/ EGFR signalling pathway. Bves is also expressed in nurse cells during oogenesis and its transcripts are then translocated into the oocyte. Expression of bves antisense RNA during oogenesis causes reduced viability in the resulting embryos. There is a failure in the migration of pole cells from the posterior towards the antero-dorsal side of the embryo, probably resulting from abnormal germband extension and we suggest that bves is essential for normal embryonic development.

Bves directly interacts with GEFT, and controls cell shape and movement through regulation of Rac1/Cdc42 activity

“…Global inactivation of the murine Bves gene leads to defects in skeletal muscle repair by satellite cells (7), whereas knockdown of Bves in cultured epithelia results in defects in wound healing (13). Finally, RNA interference analysis in Drosophila inhibits germ cell migration (16). The described interaction with a component of the Rac1/Cdc42 signaling pathway may provide the first molecular mechanism to explain these cellular/embryonic phenotypes observed upon 4.…”

“…Mice null for the bves gene are delayed in regeneration of skeletal muscle upon injury (7). A recent report demonstrates that Bves knockdown by using antisense RNA during Drosophila oogenesis results in failure of pole cells to migrate properly to the anterodorsal side of the embryo (16). Despite these studies, no direct molecular mechanism for any of these phenotypes exists at this time.…”

Regulated adhesion as a driving force of gastrulation movements

“…Ca 2+ -independent cell-cell adhesion molecules that are required for gastrulation movements include Bves and Echinoid. Xenopus and Drosophila Bves and Popeye family members have relatively short EC domains, a three-pass TM and a long intracellular domain (Lin et al, 2007;Ripley et al, 2006). Echinoid, a Drosophila nectin-like immunoglobulin cell-adhesion molecule (Ig-CAM), clusters with classical cadherins via their cytoplasmic binding partners afadin and α-catenin.…”

Expression pattern of Popdc2 during mouse embryogenesis and in the adult

“…There is a single Popdc gene (Dbves) found in Drosophila (Lin et al, 2007), two genes are present in urochordates (Davidson et al, 2003), and three genes (Bves/Popdc1, Popdc2, and Popdc3) exist in vertebrates (Brand, 2005). Bves/Popdc1 and Popdc3 are present on the same chromosomal locus, while Popdc2 is located on a different chromosome (Andrée et al, 2000).…”

“…A null mutation of Bves/Popdc1 has been generated and no embryonic lethality was reported; however, skeletal muscle regeneration in the adult was impaired (Andrée et al, 2002). A knockdown of Dbves using heat-shock antisense expression resulted in embryonic lethality displaying abnormal germ band extension (Lin et al, 2007). Impaired epithelial movements during early embryonic development was observed after knockdown of Bves/Popdc1 in Xenopus (Ripley et al, 2006).…”