The Human Protein Atlas as a proteomic resource for biomarker discovery.

The analysis of tissue-specific expression at both the gene and protein levels is vital for understanding human biology and disease. Antibody-based proteomics provides a strategy for the systematic generation of antibodies against all human proteins to combine with protein profiling in tissues and cells using tissue microarrays, immunohistochemistry and immunofluorescence. The Human Protein Atlas project was launched in 2003 with the aim of creating a map of protein expression patterns in normal cells, tissues and cancer. At present, 11,200 unique proteins corresponding to over 50% of all human protein-encoding genes have been analysed. All protein expression data, including underlying high-resolution images, are published on the free and publically available Human Protein Atlas portal (http://www.proteinatlas.org). This database provides an important source of information for numerous biomedical research projects, including biomarker discovery efforts. Moreover, the global analysis of how our genome is expressed at the protein level has provided basic knowledge on the ubiquitous expression of a large proportion of our proteins and revealed the paucity of cell- and tissue-type-specific proteins.

Early identification of retinal subtypes in the developing, pre-laminated chick retina using the transcription factors Prox1, Lim1, Ap2alpha, Pax6, Isl1, Isl2, Lim3 and Chx10.

In this study, antibodies toward the transcription factors Prox1, Lim1, Ap2alpha, Pax6, Isl1, Isl2, Lim3 and Chx10 were used to identify and distinguish between developing cell types in the pre-laminated chick retina. The spatio-temporal expression patterns were analysed from embryonic day 3 (E3) to E9, thus covering a time-span from the onset of retinal cell-fate determination to when retinal laminas can be distinguished. Most transcription factors were found at early stages of development, enabling us to trace various precursor cell populations throughout the lamination process. With time, each transcription factor expression became restricted to distinct laminas or sub-laminas of the maturing retina. These early emerging patterns were compared and found to be consistent with those of the hatched chick retina, where the outer nuclear layer label for Lim3, Isl1 and Isl2. In the inner nuclear layer, horizontal cells labeled for Prox1, Lim1, Isl1, Ap2alpha and Pax6, bipolar cell labeled for Lim3, Isl1 and Chx10 and amacrine cells labeled for Ap2alpha, Isl1 and Pax6. The ganglion cell layer labeled for Isl1, Pax6 and Isl2. The immunolabeling patterns of Lim3 and Isl2 have not previously been described in detail.