Difference of gene expression between the central and the peripheral epithelia of the bovine lens

Equatorial lens epithelial cells proliferate and differentiate into fiber cells throughout life, while central lens epithelial cells proliferate little and do not form fiber cells. This study aimed to investigate the differences in gene expression between the central and the peripheral epithelial cells of the bovine lens.

The results suggested that there were distinctly different genome activities, including a specific group of pathways, between central and peripheral lens epithelial cells.

Lens epithelia were dissected into central (<or= 11.5 mm diameter, cLEC) and peripheral regions (pLEC). The differences in gene expression and protein accumulation between these two regions were assayed by microarray analysis and two-dimensional electrophoresis (2-DE) combined with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). Differently expressed proteins were validated by immunoanalyses.

By microarray analysis, 67 transcripts were at least two-fold lower and 269 at least two-fold higher in pLEC compared with that in cLEC. Thirty-four protein spots, including 20 in cLEC and 14 in pLEC, were identified by two dimensional electrophoresis and mass spectrometry. Of these 34 protein products, 28 were represented by probe sets on the microarray. Nine transcripts changed in the same direction and four transcripts in the opposite direction to their protein products. Immunoanalyses revealed that three (mitogen-activated protein kinase 1 (MAPK1), nidogen (NID), small nuclear ribonucleoprotein N (SNRPN)) out of four transcripts with opposite change between 2-DE and microarray assay showed the same changes as the results of 2-DE gel analyses. The genes differently expressed between cLEC and pLEC mainly include those related to the MAPK, transforming growth factor beta (TGFbeta) signaling and glycolysis pathways.