Localization of porcine CD29 transcripts and protein in pig cells and tissues by RT-PCR and immunohistochemistry

Integrins are heterodimeric cell adhesion proteins with major roles in a variety of biological processes ranging from cell migration to tissue organization, immune and non-immune defense mechanisms and oncogenic transformation. Members of the β1 integrin subfamily are composed of a β1 subunit (CD29) non-covalently associated with different α subunits to constitute a group of transmembrane glycoproteins that participate in many physiologically important events. Here, we have studied the CD29 expression in porcine tissues and cells at two different levels: expression of the CD29 mRNA by RT-PCR and localization of the protein by immunohistochemistry. CD29 transcripts were detected in a variety of tissues and cells: platelets, PBMC, granulocytes, alveolar macrophages, smooth muscle, intestine, lung, liver, spleen, lymph node, skin, testis, heart, kidney and bone marrow. Our results suggest that CD29 gene transcription occurs in all organs examined, although with different intensities. The precise localization of CD29 protein in paraffin-embedded tissues was detected by using a specific polyclonal antibody indicating that its expression is limited to smooth muscle, epithelium cells, endothelium of blood vessels and myeloid cells and is no detectable in cells of the lymphoid lineage. The distribution of the CD29 in normal tissues provide insight into the physiological function of the porcine β1 integrins and should be of importance in understanding the role of this integrin family in pathological processes.