Characterization of the O-GlcNAc protein modification in Xenopus laevis oocyte during oogenesis and progesterone-stimulated maturation.
Little information exists about single N-acetylglucosamine modifications on proteins in growth and developmental model systems. To explore these phenomena, Xenopus laevis oocytes from stages I-VI of oogenesis were isolated and proteins analyzed on SDS-PAGE. The proteins were probed with antibodies specific for O-GlcNAc. Levels of the O-GlcNAc protein modification were highest in stages I and II, while decreasing in stages III-VI. The reduction in amount of O-GlcNAc-modified proteins was correlated to increases in apparent O-GlcNAcase (streptozotocin-inhibitable neutral hexosaminidase), activity involved in removing protein monoglycosylations. The O-GlcNAc modification was also characterized during progesterone-stimulated oocyte maturation. Although O-GlcNAcase activity appeared relatively constant between quiescent and matured stage VI oocytes, a small decrease in the levels of both total and specific O-GlcNAc-modified proteins was observed. Investigating the function of O-GlcNAc during maturation, oocytes were incubated with compounds known to modulate the levels of the O-GlcNAc protein modification and then stimulated to mature. Oocytes treated with compounds known to increase O-glycosylation consistently matured slower than non-treated controls, while oocytes treated with compounds that decrease O-glycosylation matured slightly faster than controls. The O-GlcNAc modification may play important roles in both the developmental and cell division processes of X. laevis oocytes.
Slawson
Chad
C
Department of Chemistry, University of South Florida, 4202 Fowler Avenue, Tampa, FL 33620, USA.
Shafii
Susan
S
Amburgey
James
J
Potter
Robert
R
D000117:Acetylglucosamine / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D006031:Glycosylation; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism*; D009866:Oogenesis; D011374:Progesterone / Q000494:pharmacology*; D011506:Proteins / Q000032:analysis / Q000378:metabolism*; D012694:Serine / Q000737:chemistry; D015398:Signal Transduction; D013912:Threonine / Q000737:chemistry; D014982:Xenopus laevis; D001619:beta-N-Acetylhexosaminidases / Q000037:antagonists & inhibitors / Q000378:metabolism
D011506:Proteins; D013912:Threonine; D012694:Serine; D011374:Progesterone; D001619:beta-N-Acetylhexosaminidases; D000117:Acetylglucosamine