COMPARISON OF THE EFFICACY OF RNALATER PRESERVED AND FRESH TISSUE IN GENE EXPRESSION STUDY OF FISH

Abstract

RNA isolation from tissues is an important methodology and a prerequisite for studying gene expression since all
molecular biology methodologies and techniques do not occur at the same time. Furthermore, molecular biology
research is heavily reliant on the use of stored samples. As a result, this study was conducted to compare the effect
of RNALater stored fish tissue samples on isolated RNA integrity using the spectrophotometric method, and gene
expression using quantitative RT-PCR. Clarias gariepinus tissues were collected and immersed in an RNAlater
buffer before being stored at 4 oC for 14 days, at the inception of nucleic acid isolation, fresh tissue was included
with the stored RNALater tissues. Results revealed that tissue storage in RNALater buffer has no effect on the
purity and concentration of the RNA isolates. This study however shows that fresh tissue batch had a higher
expression of the innate immune gene TNF-α, (i.e., of 0.411-fold expression higher) than the RNA-later batch
(0.097). While RNALater effectively preserves RNA integrity in Clarias gariepinus tissues, it significantly alters
TNF-α gene expression compared to fresh tissue (0.411-fold vs. 0.097-fold). This highlights the importance of
careful storage method selection for accurate gene quantification studies.