Identification of differentially expressed genes in mouse Pax6 heterozygous lenses

PURPOSE. Pax6 is a critical regulator of the developing lens, other ocular tissues, central nervous system, and pancreas. Downstream targets of Pax6 are largely unknown. The present study was designed to identify differentially expressed genes in Pax6 heterozygous and normal mouse lenses. METHODS. RNAs from 8-week-old normal and Pax6 heterozygous mouse lenses were analyzed by both RT-PCR differential display and a candidate-gene approach. The expression levels of identified genes were confirmed by semiquantitative RT-PCR. RESULTS. Eight transcripts encoding phosphatase inhibitor Pip-1 protein, heat shock protein Hsp40, Purkinje cell protein Pcp4, an expressed sequence tag (EST; AA331381) originally reported in a brain-specific library, Pitx3, and CBP, were confirmed to be downregulated in the Pax6 heterozygous mouse lenses. αβ- and βA3/A1-crystallin transcripts exhibited decreased expression in Pax6 heterozygous lenses, whereas the expression levels of other crystallins were virtually unchanged. CONCLUSIONS. The present data identify eight genes with expression levels that are decreased in Pax6 heterozygous lenses and provide evidence that four functional categories of transcripts-namely, small hsps (αB-crystallin and Hsp40), crystallins (αβ- and βA3/A1-crystallin), transcription factors (Pitx-3 and CBP), and components of signal transduction cascades (Pip-1) are under direct or indirect transcriptional control by Pax6.