Ober C, Billstrand C, Kuldanek S, Tan Z
Department of Human Genetics, The University of Chicago, IL 60637, USA.
Hum Reprod. 2006 Jul;21(7):1743-8. doi: 10.1093/humrep/del036. Epub 2006 Feb 24.
HLA-G is a non-classical HLA with important immunomodulatory roles in pregnancy. A polymorphism in the promoter region, -725G, was previously associated with sporadic miscarriage in women who were unselected with respect to reproductive history. In this study, the transcription levels of different HLA-G promoter haplotypes were examined to determine whether the miscarriage-associated -725G allele influences transcription.
Five naturally occurring promoter haplotypes and three variant haplotypes created by site-directed mutagenesis were sub-cloned into luciferase expression vectors and transfected into JEG-3 cells. Expression levels of these eight haplotypes were examined in cultured cells before and after treatment with interferon-beta (IFN-beta), cytosine-5-DNA methyltransferase (M. SssI) and 5-aza-2'-deoxycytidine. Differences in expression levels between haplotypes were determined by analysis of variance (ANOVA).
Promoter haplotypes with the miscarriage-associated -725G allele were expressed at significantly higher levels in all culture conditions compared with otherwise identical haplotypes that had a -725C or -725T allele.
Variation in the HLA-G promoter region influences transcription rates. Contrary to expectations, increased expression of HLA-G may be disadvantageous in some pregnancies.
HLA - G是一种非经典的人类白细胞抗原，在妊娠过程中具有重要的免疫调节作用。启动子区域的一种多态性，即 - 725G，先前被认为与未根据生殖史进行筛选的女性散发性流产有关。在本研究中，检测了不同HLA - G启动子单倍型的转录水平，以确定与流产相关的 - 725G等位基因是否影响转录。
将五种天然存在的启动子单倍型和三种通过定点诱变产生的变异单倍型亚克隆到荧光素酶表达载体中，并转染到JEG - 3细胞中。在用β - 干扰素（IFN - β）、胞嘧啶 - 5 - 甲基转移酶（M. SssI）和5 - 氮杂 - 2'-脱氧胞苷处理前后，检测这八种单倍型在培养细胞中的表达水平。通过方差分析（ANOVA）确定单倍型之间表达水平的差异。
与具有 - 725C或 - 725T等位基因的其他相同单倍型相比，带有与流产相关的 - 725G等位基因的启动子单倍型在所有培养条件下的表达水平均显著更高。
HLA - G启动子区域的变异会影响转录速率。与预期相反，HLA - G表达增加在某些妊娠中可能是不利的。
