Identification of microRNAs and other small RNAs from the adult newt eye.

PURPOSE MicroRNAs (miRNAs) are capable of controlling gene expression by targeting complimentary sequences in many mRNAs. Thus, a small number of miRNAs are capable of regulating expression of many different genes. miRNAs have been found in all animals from Drosophila to human and they are highly conserved. This work was undertaken in order to identify such RNAs in the newt eye. METHODS Cloning of these RNAs was attempted after isolating and fractionating total RNA from the adult newt eye. A gel slice ranging from about 15 to 30 nucleotides in length was cut and the extracted RNA was cloned after several processes involving reverse transcription and linker addition. For expression analysis and verification during the process of lens regeneration we used as a probe mir-124a. RESULTS Several microRNAs, piRNAs and other small RNAS were identified. Some of them have eye specific gene targets in other species, but for many a function in the eye remains to be attributed. Expression of miR-124a showed an interesting regulation in the lens regeneration-competent dorsal iris. CONCLUSIONS The cloned miRNAs and other small RNAs are the first to be reported for this animal and might bear significance in regulating processes that are unique to the newt eye, i.e., regeneration of the lens and retina.