Abstract
Purpose:
Piwi-interacting RNAs (piRNAs), a class of small non-coding RNAs associated with Piwi, maintain genomic integrity by transposon silencing. Outside of the germline, the roles of piRNAs in somatic tissues are not fully understood. We examine if piRNAs and Piwi-like molecules are expressed in retina.
Methods:
Mice aged 8 weeks were sacrificed and the retina, liver, and testis tissues were obtained. piRNA level was assessed by quantitative reverse transcription PCR (qPCR) in mouse retina. Mouse liver and testis served as controls. In another experiment, we assessed the expression of Piwi-like genes (Piwi-like-1 to -4) in human retinal pigment epithelial (RPE) cells in vitro using qPCR.
Results:
Expression of several piRNAs was observed in mouse retina tissue. These included DQ541777, DQ555094, DQ689086, DQ705026, and DQ719597 that have previously been reported to express in somatic tissues such as liver, heart and brain. We also demonstrated mRNA expression of Piwi-like genes, particularly Piwi-like-2 and -4 genes, in cultured RPE cells.
Conclusions:
These findings indicate that piRNAs and Piwi-family proteins exist in retina. They might play important roles in the proper function of the eye.