TITLE:
The Ortholog of LYVE-1 Is Required for Thoracic Duct Formation in Zebrafish
AUTHORS:
Wen-Han Chen, Wen-Fang Tseng, Gen-Hwa Lin, Andrew Schreiner, Hsiao-Rong Chen, Mark M. Voigt, Chiou-Hwa Yuh, Jen-Leih Wu, Shuan Shian Huang, Jung San Huang
KEYWORDS:
zLyve-1; Morpholino Knockdown; Thoracic Duct; Posterior Cardinal Vein Endothelial Cells
JOURNAL NAME:
CellBio,
Vol.2 No.4,
December
5,
2013
ABSTRACT:
LYVE-1 (also termed CRSBP-1), a 120-kDa disulfide-linked
dimeric type I membrane glycoprotein, is a specific marker for lymphatic endothelial
cells (LECs) and exhibits multiple ligand (hyaluronic acid and growth
factors/cytokines) binding activity in mammals. Recent studies indicate that
LYVE-1/CRSBP-1 ligands (VEGF-A165, PDGF-BB, oligopeptides containing
the cell-surface retention sequence (CRS) motifs of VEGF-A165 and
PDGF-BB) induce opening of lymphatic intercellular junctions in vitro and in vivo. To determine the function of the ortholog of mammalian
LYVE-1 in zebrafish, we cloned it (zLyve-1). The cloned cDNA (zLyve1) encodes a 328-amino-acid type I
membrane glycoprotein. The protein and genomic structure evidence supports the
notion that the cloned zLyve-1 is the ortholog of LYVE-1 in zebrafish. zLyve-1
expressed in cultured cells by transfection exhibits hyaluronic acid binding
activity but lacks the growth factor binding activity seen in mammalian
homologs. Knockdown of zLyve-1 levels by embryo microinjection with a specific
antisense morpholino oligonucleotide (MO2) in wild-type and Tg(fli1:EGFP)-transgenic zebrafish causes
defects in thoracic duct (TD) formation. Such zebrafish injected with MO2 also
exhibit impaired TD flow (as determined by intramuscular injection of
FITC-dextran). The phenotypes in these zebrafish injected with MO2 are reversed
by co-injection with zLyve1cDNA. In situ hybridization reveals that
zLyve-1 is expressed in the posterior cardinal vein (PCV). Expression of
zLyve-1 at the highest level in the PCV occurs at 3 dpf which coincides with
the time for TD formation in zebrafish development. These results suggest
that zLyve-1 is required for TD formation. They also suggest that zLyve-1 is
distinct from mammalian LYVE-1 in its role in lymphatic function.