Abstract
Purpose: :
Translational regulation plays a critical role during metazoan cell cycles, early develpment and synaptic plasticity. One of the mechanisms to control translation is cytoplasmic polyadenylation, mediated by the cytoplasmic polyadenylation element binding protein (CPEB), which recognizes a cytoplasmic polyadenylation element (CPE) sequence in 3' UTR of specific mRNAs. An elongated polyA tail is believed to stablize the RNA and to initiate translation. Local protein translation is thought to be required for temporally and spatially coordinated initiation of development and activity–dependent synaptic plasticity. This study is to investigate CPEB–mediated translational control of molecules important to the development of the retina.
Methods: :
Several retina–related CPE–containing molecules were identified based on sequence information. Total retinal RNA was harvested from post–natal day1 (P1), P7, P12, P14, P16, P30 and P60 C57BL/6 mice. Real–time PCR was used to quantitate the mRNA expression. Polyadenylation assays (PAT) was used demonstrate the length of the polyA tails. Each developmental timepoint had three groups with 6–7 animals in each group. Each experiment was repeated at least three times to ensure statistical significance.
Results: :
Our data showed significant increases in mRNA levels for CPEB1, CPEB3, and much less–significant increases for CPEB2 and CPEB4 during early development of mouse retina. The increases in mRNAs appeared to be linear between P1 and P60. Some of the putative mRNA substrates were also upregulated, with prolonged polyadenylation at specific developmental stages. Further studies are to confirm the interaction between CPEB proteins and CPE–containing mRNAs, and to investigate the functional aspects of the regulation.
Conclusions: :
CPEB mediates the translation of CPE–containing mRNA molecules during the development of the retina.
Keywords: retina • retinal development • phosphorylation