Apolipophorin-III expression and low density lipophorin formation during embryonic development of the silkworm, Bombyx mori.
We examined the expression of apolipophorin-III (apoLp-III) during embryonic development of the silkworm Bombyx mori. ApoLp-III mRNA was first expressed 24h after oviposition, which corresponds to the time of germ band formation. The amount of apoLp-III in the eggs increased from day 2, peaked on day 4, and then gradually decreased until hatching (on day 9.5). ApoLp-III was apparently synthesized during early embryogenesis, as radioactive amino acids were incorporated into newly synthesized apoLp-III in three-day-old eggs. Moreover, radioactive apoLp-III was found only in the embryo and not in the extraembryonic tissue. KBr density gradient ultracentrifugation of egg homogenates showed that apoLp-III was associated with low-density lipophorin (LDLp). These results suggest that LDLp is required for the delivery of lipids for organogenesis during embryogenesis.
Tsuchida
Kozo
K
National Institute of Infectious Diseases, Tokyo, Japan. kozo@nih.go.jp
Yokoyama
Takeru
T
Sakudoh
Takashi
T
Katagiri
Chihiro
C
Tsurumaru
Shuichiro
S
Takada
Naoko
N
Fujimoto
Hirofumi
H
Ziegler
Rolf
R
Iwano
Hidetoshi
H
Hamano
Kunikatsu
K
Yaginuma
Toshinobu
T
D000818:Animals; D001053:Apolipoproteins / Q000235:genetics / Q000378:metabolism*; D012831:Bombyx / Q000196:embryology* / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D004625:Embryo, Nonmammalian / Q000378:metabolism*; D047108:Embryonic Development; D005260:Female; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D008074:Lipoproteins / Q000235:genetics / Q000378:metabolism*
D001053:Apolipoproteins; D019476:Insect Proteins; D008074:Lipoproteins; C042470:apolipophorin III; C032830:lipophorin