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 ResearchResearch AreasSaliva and Salivary GlandsBobek     May 30, 2016  

Saliva and Salivary Glands

LIBUSE BOBEK, PhD personal profile

Regulation of salivary gland-specific gene expression

We are particularly interested in the regulation of expression of the MUC7 gene encoding a low-molecular-mass mucin. Both in vivo and in vitro approaches are undertaken.  MUC7 is predominantly expressed in the salivary gland, but its expression was also detected in respiratory tract and lacrymal glands.

Examination of the human MUC7 expression in vivo by transgenic mice technology showed that one transgenic mice line expresses MUC7 at high level, and in the same tissue and cell specific manner as humans. We will use these mice for studies directed towards localization of the DNA sequences responsible for the tissue and cell-specific expression of this gene. We are also utilizing these mice and normal human tracheo-bronchial epithelial (NHTBE) cells to investigate the modulation of MUC7 expression by exogenous factors, such as cytokines, growth factors, bacteria, and bacterial products (LPS).

We also observed that MUC7 is expressed in a human lung epithelial cell carcinoma cell line A549, and that its expression could be modulated by inflammatory mediators.  As the first step towards understanding the underlying mechanisms responsible for controlling MUC7 gene expression, we utilized this cell line for functional analysis of the MUC7 5’-flanking region. Minimal functional promoter region was defined and several putative transcription factor-binding sites recognized.  The roles of AP1 and NF-kappaB were studied in detail. Our future studies will be directed to provide new and more detailed insight into the transcriptional regulation and signaling mechanisms that control MUC7 transcription.

Another area of Dr. Bobek's research is available at Immunology and Innate Defenses