3 research outputs found
Changes in diapause related gene expression pattern during early embryonic development in HCl-treated eggs of bivoltine silkworm Bombyx mori (Lepidoptera: Bombycidae)
Investigation of differential expression of diapause related genes (five metabolic, five heat shock protein and one translational regulatory) in HCl-treated (non-diapause) and untreated (diapause) eggs of B. mori during early embryogenesis (up to 48h following oviposition) revealed the up-regulation of sorbitol dehydrogenase upon HCl treatment, indicating increased glycogen synthesis for further embryonic development but, down-regulation of phosphofructo kinase gene expression after 18h of oviposition indicating an arrest of glycerol and sorbitol conversion. The expression of poly A binding protein gene expression was higher upon HCl treatment, revealing the initiation of translation. The expression levels of other genes analyzed did not vary significantly, except for Hsp90 and Hsp40, which were up-regulated on acid treatment until 18h. Thus, Sorbitoldehydrogenase and phosphofructo kinasegenes have a crucial role in diapause termination as evidenced by HCl treatment, while the other genes did not have major roles
Differential gene expression during early embryonic development in diapause and non-diapause eggs of multivoltine silkworm <i style="">Bombyx mori</i>
1143-1151Quantification
of the differential expression of metabolic enzyme and heat-shock protein genes
(Hsp) during early embryogenesis in
diapause and non-diapause eggs of the silkworm B. mori was carried out by semi-quantitative RT-PCR. Data analysis
revealed that, the phosphofructokinase
(PFK) expression started at a higher level in the early stage (6 h after
oviposition) in non-diapause eggs, while in diapause induced eggs, it started
at a lower level. However, the PFK
gene expression in diapause eggs was comparatively higher than in non-diapause
eggs. PFK facilitates use of
carbohydrate reserves. The lower level of PFK
gene expression in the early stage of diapause induced eggs but comparatively
higher level of expression than in non-diapause eggs is due to enzyme
inactivation via protein phosphorylation during early embryogenesis followed by
de-phosphorylation in later stage. The sorbitol
dehydrogenase-2 (SDH-2) gene was down regulated in diapause induced eggs up
to 24 h and its expression levels in diapause induced eggs coincided with that
of PFK gene at 48h in non-diapause
eggs. During carbohydrate metabolism, there is an initial temporary
accumulation of sorbitol which acts as protectant. The down regulation of SDH-2 gene during the first 24 hours in diapause induced eggs was due to the
requirement of sorbitol as protectant. However, since the diapause process
culminates by 48 h, the SDH-2 gene
expression increased and coincided with that of PFK gene expression. The trehalase
(Tre) gene expression was at a lower
level in diapause induced eggs compared to non-diapausing eggs. The induction
of Tre activity is to regulate uptake
and use of sugar by the tissues. The non-diapause eggs revealed maximum
expression of GPase gene with major
fluctuations as well as an overall higher expression compared to diapause
induced eggs. The diapause process requires less energy source which reflects
lower activity of the gene. Heat shock protein (Hsp)genes (Hsp20.4, 40, 70, and 90) revealed differential levels of
expression in both the eggs at all stages of embryonic development. The present
study thus provides an overview of the differential expression levels of
metabolic enzyme and Hsp genes in non-diapause
and diapause induced eggs of multivoltine silkworm B. mori within 48 h after oviposition, confirming the major role of
in early embryogenesis