Correlation between TSC1 gene polymorphism and epilepsy

Abstract

The correlation between tuberous sclerosis complex 1 (TSC1) gene polymorphism and epilepsy was studied. In total, 38 patients with epilepsy treated in People's Hospital of Rizhao from May 2015 to June 2016 were selected as study subjects, as the observation group, 38 healthy people in the same period were selected as the control group. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) was used to study the polymorphism of TSC1 gene in the above study subjects. The mRNA expression of TSC1 gene in the observation group and the control group was measured by fluorescence quantitative PCR, the expression of TSC1 protein in the control and observation group was measured by western blotting and ELISA. The polymorphisms of TSC1 gene in control group and observation group were analyzed by PCR-RFLP. There were three genotypes of TCS1 gene locus 142 in healthy population: CC (79.3%), CA (13.9%) and AA (6.8%), there were also three genotypes at locus 142 in the observation group: CC (21.3%), CA (26.4%) and AA (52.3%), there was significant difference in the genotypes at locus 142 between healthy population and the patients with epilepsy (P<0.05). It was observed by fluorescence quantitative PCR that there was no significant difference in the mRNA expression of TSC1 gene between the control group and the observation group (P>0.05). The expression of TSC1 gene was detected by western blot method. Western blotting showed no significant difference in TSC1 protein expression between the two groups (P>0.05). However, by determining the activity of TSC1 protein in the observation group and the control group by ELISA, it was found that TSC1 activity in healthy human body (8.95±2.41 U/ml) was much lower than that in the patients with epilepsy (29.27±4.06 U/ml), the difference was statistically significant (P<0.05). It was found that locus 142 may be located at the active center of TSC1 enzyme by homology modeling of SWISS-MODEL, the mutation of locus 142 could lead to the change of TSC1 activity. The polymorphism of locus 142 in TSC1 gene is correlated with epilepsy, that is, the increase of CA and AA content in locus 142 leads to the occurrence of epilepsy.

Keywords: SWISS-MODEL; epilepsy; gene polymorphism; homology modeling; tuberous sclerosis complex 1.

Figure 1.

Results of tuberous sclerosis complex 1 (TSC1) gene amplification in healthy people and epilepsy patients. M, DL10,000; S1-S4, TSC1 gene amplification results in epilepsy patients; S5-S8, amplification of TSC1 gene in healthy population.

Figure 2.

Tuberous sclerosis complex 1 (TSC1) polymorphism in epilepsy patients and healthy people. There were 2 bands in epilepsy patients (S1-S2) TSC1 after digested by EcoR72I; there were 3 bands in healthy population (S3-S4) TSC1 gene after digested by EcoR72I.

Figure 3.

Tuberous sclerosis complex 1 (TSC1) gene mRNA expression differences in epilepsy and healthy people. As can be seen from the figure, the relative expression level of TSC1 in patients with epilepsy was 1.2 times of its mRNA expression in healthy population.

Figure 4.

Western blot method to determine expression differences of tuberous sclerosis complex 1 (TSC1) protein in patients with epilepsy and healthy people. S1-S2, expression of TSC1 protein in patients with epilepsy; S3-4, expression of TSC1 protein in healthy population. It can be seen from the figure, there was no significant difference in terms of TSC1 expression in patients with epilepsy and healthy population.

Figure 5.

Detection of tuberous sclerosis complex 1 (TSC1) protein activity in the control and observation groups by enzyme-linked immunosorbent assay (ELISA). It can be seen from the figure, there was a significant difference in TSC1 enzyme activity between epilepsy patients and healthy people.

Figure 6.

Analysis of tuberous sclerosis complex 1 (TSC1) protein homology modeling. The SWISS-MODEL homology modeling revealed that the locus 142 (the rod-like structure indicated by the arrow) was the active center of TSC1 protein.