Expression of heat shock protein 70a mRNA in Bombyx mori diapause eggs.
In an effort to understand whether heat shock protein 70 (Hsp70) participates in the environmental 5 degrees C signal reception/transduction toward breaking embryonic diapause of the silkworm Bombyx mori, we isolated a cDNA for Hsp70a and examined the expression of Hsp70a mRNA in B. mori diapause and nondiapause eggs by quantitative real-time PCR. Hsp70a mRNA gradually increased in diapause eggs continuously kept at 25 degrees C after oviposition to maintain diapause. When diapause eggs were exposed to the diapause-terminating condition of 5 degrees C beginning at 2 days post-oviposition, Hsp70a mRNA increased beginning at 5 days post-cold treatment. Even in nondiapause eggs, Hsp70a mRNA increased slightly with exposure to 5 degrees C. These results suggest that Hsp70a is involved in reception/transduction of the diapause-terminating (5 degrees C) signal via gene activation. The expression patterns of Hsp70a mRNA are discussed in relation to those of the cold-response gene Samui.
Moribe
Yoriko
Y
Sericulture & Entomoresources, Graduate School of Bioagricultural Sciences, Nagoya University, Chikusa, Nagoya, Japan.
Oka
Keigo
K
Niimi
Teruyuki
T
Yamashita
Okitsugu
O
Yaginuma
Toshinobu
T
D000064:Acclimatization / Q000502:physiology*; D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000235:genetics / Q000378:metabolism* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000235:genetics; D005786:Gene Expression Regulation / Q000502:physiology*; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D010063:Ovum / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D013696:Temperature
D017931:DNA Primers; D018076:DNA, Complementary; D018840:HSP70 Heat-Shock Proteins; D012333:RNA, Messenger