# Impact of the 294 bp SINE Insertion in 5′UTR of the GLYATL3 Gene on Gene Expression and Phenotypic Variation

## TL;DR

A DNA fragment insertion near the GLYATL3 gene affects gene activity and growth traits in pigs, potentially aiding breeding programs.

## Contribution

Identifies a SINE insertion's role in regulating GLYATL3 expression and influencing pig growth traits.

## Key findings

- SINE insertion is present in purebred pigs but absent in hybrids.
- The insertion increases GLYATL3 expression in the cerebellum and boosts promoter activity.
- Pigs with the insertion show growth differences at 30 kg body weight.

## Abstract

This study explored how a specific DNA fragment (SINE) inserted near the GLYATL3 gene affects gene expression and physical traits in pigs. Researchers tested 15 pig breeds and found that the SINE insertion was absent in hybrid pigs but present in all purebreds. Pigs with the SINE insertion showed differences in growth, particularly when reaching 30 kg in weight. Experiments revealed that the SINE insertion boosts GLYATL3 gene activity in the brain and enhances the function of a gene promoter linked to development. These findings suggest that this SINE insertion may influence traits like growth by regulating GLYATL3 expression in pigs.

SINEs are one type of the most frequently found DNA repetitive sequences in the eukaryotic genome. The polymorphism generated by SINE insertion may affect proximal host genes and even cause phenotypic variations in domestic animals. Glycine N-acyltransferase-like 3 (GLYATL3) is a member of the N-acyltransferase family which may play a role in amino acid and fatty acid metabolism. Previous studies have identified short interspersed nuclear element (SINE) insertion sites in the 5′UTR region of GLYATL3. This study investigated the effects of the 294 bp SINE insertion on GLYATL3 expression and phenotypic variation. The polymerase chain reaction (PCR) was used to determine the distribution of GLYATL3-SINE-RIP in 15 pig breeds. SINE insertions were absent in hybrid pigs and present in all purebred pigs. Correlation analysis further revealed significant differences in SINE+/+ and SINE−/− individuals when they reached 30 kg of body weight. In light of these findings, qPCR revealed that the SINE insertion significantly increased GLYATL3 expression in the cerebellum of Mi pigs. Additionally, dual-luciferase reporter assays confirmed that the SINE insertion significantly enhanced the activity of the Oct4 promoter. Preliminary evidence indicates the SINE insertion may modulate an increase in the growth rate of pigs through transcriptional regulation of GLYATL3. As a new type marker, this SINE-insertion polymorphism may assist genetic selection to optimize growth traits in porcine breeding programs.