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Indian Journal of Experimental Biology (IJEB) >
IJEB Vol.48 [2010] >
IJEB Vol.48(11) [November 2010] >
| Title: | Differential gene expression during early embryonic development in diapause and non-diapause eggs of multivoltine silkworm Bombyx mori |
| Authors: | Ponnuvel, Kangayam M
Murthy, Geetha N
Awasthi, Arvind K
Rao, Guruprasad
Vijayaprakash, Nanjappa B |
| Keywords: | Bombyx mori
Diapause
Differential gene expression
Embryogenesis
Multivoltine |
| Issue Date: | Nov-2010 |
| Publisher: | NISCAIR-CSIR, India |
| Abstract: | Quantification
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. |
| Page(s): | 1143-1151 |
| CC License: |  CC Attribution- Noncommercial-No Derivative Works 2.5 India |
| ISSN: | 0975-1009 (Online); 0019-5189 (Print) |
| Source: | IJEB Vol.48(11) [November 2010]
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