Analysis of Maxi-K alpha subunit splice variants in human myometrium

被引：13

作者：

Curley M. ^{[1
]}

Morrison J.J. ^{[1
,2
,3
]}

Smith T.J. ^{[1
]}

机构：

[1] National Ctr. for Biomed. Eng. Sci., National University of Ireland, Galway

[2] Department of Obstetrics/Gynaecology, National University of Ireland, Galway

[3] Clinical Science Institute, University College Hospital Galway, Galway, Newcastle Road

来源：

Reproductive Biology and Endocrinology | / 2卷 / 1期

关键词：

Voltage Sensitivity; Human Myometrium; Labour Onset; Subunit mRNA Expression; Pregnant Myometrium;

D O I：

10.1186/1477-7827-2-67

中图分类号：

学科分类号：

摘要：

Background: Large-conductance, calcium-activated potassium (Maxi-K) channels are implicated in the modulation of human uterine contractions and myometrial Ca2+ homeostasis. However, the regulatory mechanism(s) governing the expression of Maxi-K channels with decreased calcium sensitivity at parturition are unclear. The objectives of this study were to investigate mRNA expression of the Maxi-K alpha subunit, and that of its splice variants, in human non-pregnant and pregnant myometrium, prior to and after labour onset, to determine whether altered expression of these splice variants is associated with decreased calcium sensitivity observed at labour onset. Methods: Myometrial biopsies were obtained at hysterectomy (non-pregnant, NP), and at Caesarean section, at elective (pregnant not-in-labour, PNL) and intrapartum (pregnant in-labour, PL) procedures. RNA was extracted from all biopsies and quantitative real-time RT-PCR was used to investigate for possible differential expression of the Maxi-K alpha subunit, and that of its splice variants, between these functionally-distinct myometrial tissue sets. Results: RT-PCR analysis identified the presence of a 132 bp and an 87 bp spliced exon of the Maxi-K alpha subunit in all three myometrial tissue sets. Quantitative real-time PCR indicated a decrease in the expression of the Maxi-K alpha subunit with labour onset. While there was no change in the proportion of Maxi-K alpha subunits expressing the 87 bp spliced exon, the proportion of alpha subunits expressing the 132 bp spliced exon was significantly increased with labour onset, compared to both non-pregnant and pregnant not-in-labour tissues. An increased proportion of 132 bp exon-containing alpha subunit variants with labour onset is of interest, as channels expressing this spliced exon have decreased calcium and voltage sensitivities. Conclusions: Our findings suggest that decreased Maxi-K alpha subunit mRNA expression in human myometrium at labour onset, coupled to an increased proportion of Maxi-K channels expressing the 132 bp spliced exon, may be linked to decreased Maxi-K channel calcium and voltage sensitivity, thereby promoting enhanced uterine activity at the time of labour. © 2004 Curley et al; licensee BioMed Central Ltd.

引用

页数：9

共 33 条

[1]

Wray S., Uterine contraction and physiological mechanisms of modulation, Am. J. Physiol., 264, (1993)

[2]

Kawarbayashi T., Electrophysiology of the Human Myometrium, pp. 148-172, (1994)

[3]

Brayden J.E., Potassium channels in vascular smooth muscle, Clin. Exp. Pharmacol. Physiol., 23, pp. 1069-1076, (1996)

[4]

Meera P., Anwer K., Monga M., Oberti C., Stefani E., Toro L., Sanborn B.M., Relaxin stimulates myometrial calcium-activated potassium channel activity via protein kinase A, Am. J. Physiol., 269, (1995)

[5]

Anwer K., Oberti C., Perez G.J., Perez-Reyes N., McDougall J.K., Monga M., Sanborn B.M., Stefani E., Toro L., Calcium-activated K+ channels as modulators of human myometrial contractile activity, Am. J. Physiol., 265, (1993)

[6]

Khan R.N., Smith S.K., Ashford M.L.J., Contribution of calcium-sensitive potassium channels to NS1619-induced relaxation in human pregnant myometrium, Hum. Reprod., 13, pp. 208-213, (1998)

[7]

Adelman J.P., Shen K.Z., Kavanagh M.P., Warren R.A., Wu Y.M., Lagrutta A., Bond C.T., North R.A., Calcium-activated potassium channels expressed from clonal complementary DNAs, Neuron, 9, pp. 209-216, (1992)

[8]

Knaus H.-G., Folander K., Garcia-Calvo M., Garcia M.L., Kaczorowski G.J., Smith M., Swanson R., Primary sequence and immunological characterization of β-subunit of high conductance Ca2+-activated K+ channel from smooth muscle, J. Biol. Chem., 269, 25, pp. 17274-17278, (1994)

[9]

McManus O.B., Helms L.M.H., Pallanck L., Ganetzky B., Swanson R., Leonard R.J., Functional role of the β subunit of high conductance calcium-activated potassium channels, Neuron, 14, pp. 645-650, (1995)

[10]

Wallner M., Meera P., Ottolia M., Kaczorowski G.J., Latorre R., Garcia M.L., Stefani E., Toro L., Characterization of and modulation by a β-subunit of a human Maxi KCa channel cloned from myometrium, Receptors and Channels, 3, pp. 185-199, (1995)

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