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MicroRNAs (miRNAs) are small endogenous non-coding RNA molecules and considered as major
regulators in eukaryotic gene expression. After maturation they become single-stranded and bind to
target mRNA molecules decreasing their translation. This process is called RNA interference (RNAi).
MiRNAs are broadly distributed in many tissues and regulate amongst others differentiaton,
carcinogenesis and pluripotency. There are reports of miRNAs in murine and human sperms that enter
the oocyte at fertilisation (Amanai et al. 2006; Ostermeier et al. 2005). But the levels of these spermborne
miRNAs are low compared to those of unfertilized oocytes, and fertilization did not alter the oocyte
miRNA repertoire. So their role within fertilization remains unclear (Amanai et al. 2006).
The aim of this study is to find and characterise potential regulating microRNA in porcine sperms and
try to figure out, wether they interfere with fertilization.
Material & Methods: Fresh porcine semen of different pig races was filtered through gaze and
diluted with DiluPorc (Sinus Biochemistry & Electrophoresis GmbH). Swim up was used to separate the
motile sperms from nonmotile ones and somatic cells, followed by several washing steps with PBS
(PAA). Total RNA was isolated from agile sperms using mirVana miRNA Isolation Kit (Ambion). After
quality control with RNA Nano Chips (Agilent Technologies) in a Agilent 2100 bioanalyser the RNA was
labeled with fluorescent Dyes (Cy3 or Cy5, GE Healthcare) and hybridised to a miRNA microarray
consisting of the mirVana miRNA Probe Set 1564V1Aug05 (Ambion) which was spotted onto Nexterion
E Slides (Schott).The scanning was performed using a GenePix 4000B (Axon Instruments).
Results: The testing of different boars revealed a set of 37 different miRNAs present in the sperms
so far. Ten of them are present in all animals. These include miR_let_7a, let_7b, let_7c, miR_16,
miR_191, miR_26a, miR_30d and miR_449. Five miRNAs are present in almost two animals for example
miR_15b and miR_122a and the sperms of one animal expresses 17 miRNAs like miR_103 and
Conclusion: A compilation of different miRNAs is found in porcine sperms. Their distribution is
obviously changing between individuals.