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Spatial transcription of CYP1A in fish liver.

Olsvik PA, Lie KK, Saele Ø, Sanden M - BMC Physiol. (2007)

Bottom Line: Transcription of CYP1A and GST was higher in the middle section of the liver compared to the distal and proximal parts of the organ.Overall, the qRT-PCR and ISH results reported here suggest that gene expression analysis should be performed on as pure cell populations as possible.If bulk tissue samples are to be used, one should always check how evenly the target genes are expressed in tissue sections and organs in every study.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Institute of Nutrition and Seafood Research, N-5817 Bergen, Norway. pal.olsvik@nifes.no

ABSTRACT

Background: The aim of this work was to study how evenly detoxifying genes are transcribed spatially in liver tissue of fish. Ten Atlantic salmon Salmo salar were intraperitoneally injected with 50 mg/kg of the strong CYP1A inducer beta-naphthoflavone and liver tissue harvested seven days later. The liver from 10 control and 10 exposed fish were split into eight sections, RNA extracted and three reference (beta-actin, elongation factor 1AB (EF1AB)) and two detoxifying genes (CYP1A and GST) quantified with real-time RT-PCR. The cellular localization of the EF1AB and CYP1A mRNA in the liver of control and beta-naphthoflavone treated fish was then determined by in situ hybridization (ISH) using EF1AB and CYP1A biotinylated oligonucleotide probes.

Results: The study shows that genes encoding phase I and phase II conjugating enzymes are unevenly transcribed in different parts of the liver of Atlantic salmon seven days after a single-dose of beta-naphthoflavone exposure. Transcription of CYP1A and GST was higher in the middle section of the liver compared to the distal and proximal parts of the organ. The ISH data suggest that CYP1A transcription happens mainly in hepatocyte cells in the liver, and that hepatocytes in the vicinity of blood vessels respond stronger to beta-naphthoflavone than cells further away from the blood supply.

Conclusion: Overall, the qRT-PCR and ISH results reported here suggest that gene expression analysis should be performed on as pure cell populations as possible. If bulk tissue samples are to be used, one should always check how evenly the target genes are expressed in tissue sections and organs in every study.

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Related in: MedlinePlus

Mean normalized expression (MNE) of CYP1A and GST in gills (A and C) and head kidney (B and D) of Atlantic salmon Salmo salar exposed to β-naphthoflavone.
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Figure 3: Mean normalized expression (MNE) of CYP1A and GST in gills (A and C) and head kidney (B and D) of Atlantic salmon Salmo salar exposed to β-naphthoflavone.

Mentions: In order to check how the BNF treatment affected other organs in the fish, mRNA expression levels of CYP1A and GST were also quantified in gills and head kidney (Fig. 3). Measurements were obtained from the same six individuals that were used to study expression patters in liver. The results revealed that BNF acted as a strong CYP1A inducer also in these organs. In gills (Fig. 3A), CYP1A mRNA expression showed a 31-fold induction (t-test, P < 0.0001). Baseline CYP1A mRNA levels in head kidney were very low (Fig. 3B). The transcription level of this gene was 2261 fold higher in BNF-exposed animals compared to control animals (t-test, P < 0.0001). GST mRNA induction in exposed animals was more modest in gills and head kidney. The fold change for GST mRNA expression was 2.2 in gills and 3.3 in head kidney; the expression differences in the latter organ were significant (t-test, P < 0.022).


Spatial transcription of CYP1A in fish liver.

Olsvik PA, Lie KK, Saele Ø, Sanden M - BMC Physiol. (2007)

Mean normalized expression (MNE) of CYP1A and GST in gills (A and C) and head kidney (B and D) of Atlantic salmon Salmo salar exposed to β-naphthoflavone.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2238752&req=5

Figure 3: Mean normalized expression (MNE) of CYP1A and GST in gills (A and C) and head kidney (B and D) of Atlantic salmon Salmo salar exposed to β-naphthoflavone.
Mentions: In order to check how the BNF treatment affected other organs in the fish, mRNA expression levels of CYP1A and GST were also quantified in gills and head kidney (Fig. 3). Measurements were obtained from the same six individuals that were used to study expression patters in liver. The results revealed that BNF acted as a strong CYP1A inducer also in these organs. In gills (Fig. 3A), CYP1A mRNA expression showed a 31-fold induction (t-test, P < 0.0001). Baseline CYP1A mRNA levels in head kidney were very low (Fig. 3B). The transcription level of this gene was 2261 fold higher in BNF-exposed animals compared to control animals (t-test, P < 0.0001). GST mRNA induction in exposed animals was more modest in gills and head kidney. The fold change for GST mRNA expression was 2.2 in gills and 3.3 in head kidney; the expression differences in the latter organ were significant (t-test, P < 0.022).

Bottom Line: Transcription of CYP1A and GST was higher in the middle section of the liver compared to the distal and proximal parts of the organ.Overall, the qRT-PCR and ISH results reported here suggest that gene expression analysis should be performed on as pure cell populations as possible.If bulk tissue samples are to be used, one should always check how evenly the target genes are expressed in tissue sections and organs in every study.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Institute of Nutrition and Seafood Research, N-5817 Bergen, Norway. pal.olsvik@nifes.no

ABSTRACT

Background: The aim of this work was to study how evenly detoxifying genes are transcribed spatially in liver tissue of fish. Ten Atlantic salmon Salmo salar were intraperitoneally injected with 50 mg/kg of the strong CYP1A inducer beta-naphthoflavone and liver tissue harvested seven days later. The liver from 10 control and 10 exposed fish were split into eight sections, RNA extracted and three reference (beta-actin, elongation factor 1AB (EF1AB)) and two detoxifying genes (CYP1A and GST) quantified with real-time RT-PCR. The cellular localization of the EF1AB and CYP1A mRNA in the liver of control and beta-naphthoflavone treated fish was then determined by in situ hybridization (ISH) using EF1AB and CYP1A biotinylated oligonucleotide probes.

Results: The study shows that genes encoding phase I and phase II conjugating enzymes are unevenly transcribed in different parts of the liver of Atlantic salmon seven days after a single-dose of beta-naphthoflavone exposure. Transcription of CYP1A and GST was higher in the middle section of the liver compared to the distal and proximal parts of the organ. The ISH data suggest that CYP1A transcription happens mainly in hepatocyte cells in the liver, and that hepatocytes in the vicinity of blood vessels respond stronger to beta-naphthoflavone than cells further away from the blood supply.

Conclusion: Overall, the qRT-PCR and ISH results reported here suggest that gene expression analysis should be performed on as pure cell populations as possible. If bulk tissue samples are to be used, one should always check how evenly the target genes are expressed in tissue sections and organs in every study.

Show MeSH
Related in: MedlinePlus