Expression of RXR, EcR, E75 and VtG mRNA levels in the hepatopancreas and ovary of the freshwater edible crab, Oziothelphusa senex senex (Fabricius, 1798) during different vitellogenic stages

• Published in: Die Naturwissenschaften Vol. 102; no. 3-4; p. 20
• Main Authors: Girish, B. P., Swetha, CH, Reddy, P. Sreenivasula
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-04-2015
• Subjects: Animals; Arthropod Proteins - genetics; Biomedical and Life Sciences; Brachyura - genetics; Brachyura - growth & development; Brachyura - metabolism; Environment; Female; Fresh Water; Gene Expression Regulation, Developmental; Hepatopancreas - metabolism; Life Sciences; Original Paper; Ovary - metabolism; Receptors, Steroid - genetics; Retinoid X Receptors - genetics; RNA, Messenger - metabolism; Vitellogenesis - genetics; Crustaceans; Haemolymph; Vitellogenesis; Immunoprecipitation; Ovary and hepatopancreas
• ISSN: 0028-1042; 1432-1904
• DOI: 10.1007/s00114-015-1272-9

The objective of the present study was to investigate the expression profile of retinoid X receptor (
RXR
), ecdysone receptor (
EcR
) and ecdysone inducible gene (
E75
) in the hepatopancreas and ovary of
Oziothelphusa senex senex
during different vitellogenic stages.
RXR
,
EcR
and
E75
complementary DNAs (cDNAs) were isolated from the ovaries, while vitellogenin (
VtG
) cDNA was isolated from the hepatopancreas of vitellogenic female crab. Deduced amino acid sequence of the messenger RNAs (mRNAs) of
RXR
,
EcR
and
E75
showed more than 80 % identity with their respective mRNAs of other brachyurans.
VtG
mRNA was not detected in the ovary throughout vitellogenic stages.
RXR
and
EcR
were significantly increased in the ovaries during vitellogenic stage I. The levels of
EcR
,
E75
and
VtG
in the hepatopancreas elevated significantly during vitellogenic stages I and II, whereas the levels of
RXR
elevated only in vitellogenic stage I. During vitellogenic stage III, the levels of
RXR
,
EcR
and
VtG
in the hepatopancreas were significantly decreased. Immunoprecipitation analysis revealed the presence of VtG in the haemolymph, hepatopancreas and ovary extracts from the females but absent in haemolymph and hepatopancreas extract of males. It can be inferred that RXR, EcR and E75 are involved in the regulation of synthesis of VtG in hepatopancreas, whereas in ovary, it is hypothesized that they play an important role in the uptake of VtG from the haemolymph, probably by regulating the levels of vitellogenin receptor. These are the first data showing an association between the expression levels of
RXR
,
EcR
and
E75
and vitellogenesis and provide an alternative molecular intervention mechanism to the traditional eyestalk ablation to induce vitellogenesis and ovarian maturation in crustaceans.