Coordinated age-dependent and pancreatic-specific expression of mouse Reg2Reg3α, and Reg3β genes

Abstract

Reg family proteins such as Reg1 and islet neogenesis-associated protein (INGAP) have long been implicated in the growth and/or neogenesis of pancreatic islet cells. Recent reports further suggest similar roles to be played by new members such as Reg2, Reg3α, and Reg3β. We have studied their age-, isoform-, and tissue-specific expressions. RNA and protein were isolated from C57BL/6 mice aged 7, 30, and 90 days. Using real-time polymerase chain reaction, the levels of Reg gene expression in the pancreas were 20–600-fold higher than that in other tissues (≫duodenum>stomach>liver); gene expression of Reg2, Reg3α, and Reg3β was age dependent as it was hardly detectable at day 7, increased drastically at day 30, and significantly decreased at day 90; the levels of pancreatic proteins displayed similar age-dependent variations. Using dual-labeled immunofluorescence, Reg2, Reg3α, and Reg3β were abundantly expressed in most acinar cells of the pancreas, in contrast to INGAP which exhibited stepwise increases from day 7 to day 90 and colocalized with the α-cells. These new Reg genes were mainly expressed in the pancreas, with clear age-dependent and isoform-specific patterns.

Keywords::

• Real-time PCR
• Western blot
• immunofluorescence
• Reg family proteins
• acinar cells
• INGAP

Acknowledgements

Dr Maria Petropavlovskaia of McGill University provided INGAP antibody.

Declaration of interest: This work was supported by funding from Canadian Institutes of Health Research (Grants MOP-84389 & CCI-85675) and National Science and Engineering Research Council of Canada (341205-07). J.-L.L. was a senior Chercheurs-boursier of Fonds de la recherché en santé Quebec. B.L. received fellowship support from the Research Institute of McGill University Health Centre. Y.W. was supported by China Scholarship Council (No. 2009706002). M.W. was supported by the National Key Technologies R&D Program of China during the 11th Five-Year Plan Period (No. 2009ZX09102-111). Tehmina Siddique received support from Pakistan Higher Education Commission. The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.