Molecular characterisation of the gene, LGALS13, and its putative involvement in pre-eclampsia
Date
2009-03
Authors
Postma, Alisa
Journal Title
Journal ISSN
Volume Title
Publisher
Stellenbosch : University of Stellenbosch
Abstract
Pre-eclampsia is one of the most common hypertensive disorders of
pregnancy in South Africa. Presently, the only cure for pre-eclampsia is
delivery, which brings with it, additional complications. As an alternative,
clinical management of this disorder relies on timely diagnosis.
The predictive biomarker, Placental Protein 13 (PP13), is currently used
for the early diagnosis of pre-eclampsia, in an ELISA-based diagnostic
kit, developed by Diagnostic Technologies Limited (DTL)1. A decrease in
serum PP13 levels has been reported during the first trimester of
pregnancy in women who later develop pre-eclampsia. The function of
PP13 has not been fully elucidated and it is also not known whether the
reduction in PP13 levels is a cause or an effect of the disease. The use
of PP13 as a predictive biomarker for pre-eclampsia therefore warrants a
comprehensive study of this peptide and the encoding gene, LGALS13.
The aim of this study was firstly to characterise LGALS13 using a range
of in silico tools. PP13 was found to be most homologous to the
predicted protein product of a neighbouring “putative” gene, LOC148003.
A gene conversion event between these two genes most likely underlies
the so-called “hotspot mutation” in LGALS13. Data also demonstrates
that the DelT mutation disrupts functionally and structurally important
features of the gene and peptide sequences. Through the analysis of the
putative promoter region of LGALS13, the presence of a Stimulatory
protein-1 (Sp1) binding sequence element was predicted, which has
implications for regulation of LGALS13.
Secondly, the study aimed to establish a study cohort for the
investigation of the effect that the LGALS13 genotype has on the
expression of its mRNA and protein products. Serum, plasma and whole blood samples were collected and prepared from 316 pregnant women.
Placental tissue samples were obtained from a selected group of these
subjects for RNA extraction. Once the sampling on the two remaining
targeted deliveries has occurred, the collection of samples will be
batched and sent to DTL in Israel, for PP13 measurement.
DNA was extracted from the whole blood samples obtained, and all
study participants were genotyped for seven sequence variants within
the LGALS13 gene using (i) Multiphor Single Stranded Conformational
Polymorphism and Heteroduplex (SSCP/HD) analysis, (ii) restriction
enzyme analysis and (iii) DNA sequencing. The genotype data sets will
be compared with PP13 levels when they become available, and also
with clinical parameters, once the deliveries have all occurred and the
database is complete.
This study demonstrated the power of an in silico approach to direct the
focus of future experimental work. The newly established study cohort
will be used for prospective studies aiming at a better understanding of
the role which LGALS13 and PP13 play in the early prediction of preeclampsia.
Description
Thesis (MSc (Genetics))--University of Stellenbosch, 2009.
Keywords
PP13, LGALS13, Dissertations -- Genetics, Theses -- Genetics