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Cytokeratin 19 promoter directs the expression of Cre recombinase in various epithelia of transgenic mice

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ABSTRACT

Cytokeratin 19 (K19) is expressed in various differentiated cells, including gastric, intestinal and bronchial epithelial cells, and liver duct cells. Here, we generated a transgenic mouse line, K19-Cre, in which the expression of Cre recombinase was controlled by the promoter of K19. To test the tissue distribution and excision activity of Cre recombinase, K19-Cre transgenic mice were bred with Rosa26 reporter strain and a mouse strain that carries PTEN conditional alleles (PTENLoxp/Loxp). At mRNA level, Cre was strongly expressed in the stomach, lung and intestine, while in stomach, lung, and liver at protein level. The immunoreactivity to Cre was strongly observed the cytoplasm of gastric, bronchial and intestinal epithelial cells. Cre activity was detectable in gastric, bronchial and intestinal epithelial cells, according to LacZ staining. In K19-Cre/PTEN Loxp/Loxp mice, PTEN was abrogated in stomach, intestine, lung, liver and breast, the former two of which were verified by in situ PCR. There appeared breast cancer with PTEN loss. These data suggest that K19 promoter may be a useful tool to study the pathophysiological functions of cytokeratin 19-positive cells, especially gastrointestinal epithelial cells. Cell specificity of neoplasia is not completely attributable to the cell-specific expression of oncogenes and cell-specific loss of tumor suppressor genes.

No MeSH data available.


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Breast carcinogenesis in transgenic mice with tissue-specific abrogation of PTENThere appeared the expression loss of PTEN in gastric mucosa and breast cancer in K19-Cre /PTEN Loxp/Loxp mice by immunohistochemistry A. In situ PCR showed that the deletion of PTEN exon 5 was deleted in breast cancer, gastric and intestinal epithelium with the intestine of pvillin-Cre/PTENLoxp/Loxp as a positive control B. WT, wild-type C57 mouse; HE, hematoxylin-eosin staining.
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Figure 5: Breast carcinogenesis in transgenic mice with tissue-specific abrogation of PTENThere appeared the expression loss of PTEN in gastric mucosa and breast cancer in K19-Cre /PTEN Loxp/Loxp mice by immunohistochemistry A. In situ PCR showed that the deletion of PTEN exon 5 was deleted in breast cancer, gastric and intestinal epithelium with the intestine of pvillin-Cre/PTENLoxp/Loxp as a positive control B. WT, wild-type C57 mouse; HE, hematoxylin-eosin staining.

Mentions: To check the excision activity of Cre recombinase, K19-Cre transgenic mice were crossed with the mice carrying PTEN conditional alleles (PTENLoxp/Loxp), in which both Loxp sites are inserted into introns 4 and 5 of PTEN. Therefore, Cre can delete the exon 5 to inactivate PTEN gene (Figure 4A). Additionally, we also designed primers around exon 5 as shown in Figure 4B and found that exon-abrogated and small-size bands in lung, stomach, intestine, liver and breast of K19-Cre/PTEN Loxp/Loxp mice (Figure 4C). In the target knockout mice, PTEN was not expressed in gastric mucosa and breast cancer according to the results of immunohistochemistry (Figure 5A). In addition, we found no PTEN signal in some gastric and intestinal epithelial cells according to the data of in situ PCR targeting only exon 5 (Figure 5B). It was noted that breast cancer was found with no PTEN signal in both DNA and protein levels (Figure 5A-5B). The intestine of pvillin-Cre/PTEN Loxp/Loxp mouse showed no DNA signal of PTEN exon 5, and consequently was used as a positive control.


Cytokeratin 19 promoter directs the expression of Cre recombinase in various epithelia of transgenic mice
Breast carcinogenesis in transgenic mice with tissue-specific abrogation of PTENThere appeared the expression loss of PTEN in gastric mucosa and breast cancer in K19-Cre /PTEN Loxp/Loxp mice by immunohistochemistry A. In situ PCR showed that the deletion of PTEN exon 5 was deleted in breast cancer, gastric and intestinal epithelium with the intestine of pvillin-Cre/PTENLoxp/Loxp as a positive control B. WT, wild-type C57 mouse; HE, hematoxylin-eosin staining.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5392329&req=5

Figure 5: Breast carcinogenesis in transgenic mice with tissue-specific abrogation of PTENThere appeared the expression loss of PTEN in gastric mucosa and breast cancer in K19-Cre /PTEN Loxp/Loxp mice by immunohistochemistry A. In situ PCR showed that the deletion of PTEN exon 5 was deleted in breast cancer, gastric and intestinal epithelium with the intestine of pvillin-Cre/PTENLoxp/Loxp as a positive control B. WT, wild-type C57 mouse; HE, hematoxylin-eosin staining.
Mentions: To check the excision activity of Cre recombinase, K19-Cre transgenic mice were crossed with the mice carrying PTEN conditional alleles (PTENLoxp/Loxp), in which both Loxp sites are inserted into introns 4 and 5 of PTEN. Therefore, Cre can delete the exon 5 to inactivate PTEN gene (Figure 4A). Additionally, we also designed primers around exon 5 as shown in Figure 4B and found that exon-abrogated and small-size bands in lung, stomach, intestine, liver and breast of K19-Cre/PTEN Loxp/Loxp mice (Figure 4C). In the target knockout mice, PTEN was not expressed in gastric mucosa and breast cancer according to the results of immunohistochemistry (Figure 5A). In addition, we found no PTEN signal in some gastric and intestinal epithelial cells according to the data of in situ PCR targeting only exon 5 (Figure 5B). It was noted that breast cancer was found with no PTEN signal in both DNA and protein levels (Figure 5A-5B). The intestine of pvillin-Cre/PTEN Loxp/Loxp mouse showed no DNA signal of PTEN exon 5, and consequently was used as a positive control.

View Article: PubMed Central - PubMed

ABSTRACT

Cytokeratin 19 (K19) is expressed in various differentiated cells, including gastric, intestinal and bronchial epithelial cells, and liver duct cells. Here, we generated a transgenic mouse line, K19-Cre, in which the expression of Cre recombinase was controlled by the promoter of K19. To test the tissue distribution and excision activity of Cre recombinase, K19-Cre transgenic mice were bred with Rosa26 reporter strain and a mouse strain that carries PTEN conditional alleles (PTENLoxp/Loxp). At mRNA level, Cre was strongly expressed in the stomach, lung and intestine, while in stomach, lung, and liver at protein level. The immunoreactivity to Cre was strongly observed the cytoplasm of gastric, bronchial and intestinal epithelial cells. Cre activity was detectable in gastric, bronchial and intestinal epithelial cells, according to LacZ staining. In K19-Cre/PTEN Loxp/Loxp mice, PTEN was abrogated in stomach, intestine, lung, liver and breast, the former two of which were verified by in situ PCR. There appeared breast cancer with PTEN loss. These data suggest that K19 promoter may be a useful tool to study the pathophysiological functions of cytokeratin 19-positive cells, especially gastrointestinal epithelial cells. Cell specificity of neoplasia is not completely attributable to the cell-specific expression of oncogenes and cell-specific loss of tumor suppressor genes.

No MeSH data available.


Related in: MedlinePlus