Nandi Shyam Sundar, Ghosh Pamela, Roy Sib Sankar
Molecular and Cell Biology Laboratory, Cell Biology and Physiology Division, Indian Institute of Chemical Biology, Council of Scientific and Industrial Research, Kolkata, India.
Cell Physiol Biochem. 2011;27(2):159-70. doi: 10.1159/000325218. Epub 2011 Feb 11.
PITX2, a multifunctional Paired-like homeodomain transcription factor, plays obligatory role during development of organs like heart, brain and pituitary. It regulates differentiation of vascular smooth muscle cells and hematopoietic stem cells. Although we earlier reported the Pitx2/PITX2 expression in gonad, but the expression pattern of its different isoforms in mammalian gonads especially during development is still not known. As PITX2 participates in the development of multiple organs and different homeobox genes have been shown to control gonadal functions, we wanted to investigate the role of PITX2 in gonadal development and its function. The objective of our study was to know the expression profile of different Pitx2/PITX2 isoforms and its localization throughout the development of gonads. Here we show the temporal and spatial expression pattern of Pitx2/PITX2 and its localization throughout the embryonic and postnatal stages of rat gonads. Pitx2/PITX2 expression profile reveals the differential and dimorphic expression pattern of its two isoforms PITX2B2 and-Cβ throughout the embryonic development stages and also in the postnatal stages, where it becomes more prominent. This is the first report where PITX2 homeodomain transcription factor shows isoform-specific sexually dimorphic expression. In addition, PITX2 localization was found in the embryonic ovarian primordial germ cell clusters and germ cells inside the testicular cords and also in somatic cells. In adults, ovarian granulosa and theca cells as well as germ cells inside the seminiferous tubules in testis express PITX2. All the evidences suggest that the differential expression of PITX2 might be associated with sex-specific embryonic and postnatal gonadal development and the physiological processes.
PITX2是一种多功能的成对样同源结构域转录因子，在心脏、大脑和垂体等器官的发育过程中发挥着不可或缺的作用。它调节血管平滑肌细胞和造血干细胞的分化。尽管我们之前报道过Pitx2/PITX2在性腺中的表达，但在哺乳动物性腺中，尤其是在发育过程中，其不同异构体的表达模式仍不清楚。由于PITX2参与多个器官的发育，并且已有研究表明不同的同源框基因可控制性腺功能，因此我们想要研究PITX2在性腺发育中的作用及其功能。我们研究的目的是了解不同Pitx2/PITX2异构体在性腺发育过程中的表达谱及其定位。在此，我们展示了Pitx2/PITX2在大鼠性腺胚胎期和出生后各阶段的时空表达模式及其定位。Pitx2/PITX2表达谱揭示了其两种异构体PITX2B2和-Cβ在整个胚胎发育阶段以及出生后阶段的差异表达和两性异形表达模式，且这种模式在出生后更为显著。这是首次报道PITX2同源结构域转录因子呈现异构体特异性的两性异形表达。此外，在胚胎期卵巢原始生殖细胞簇、睾丸索内的生殖细胞以及体细胞中均发现了PITX2的定位。在成年个体中，卵巢颗粒细胞、卵泡膜细胞以及睾丸生精小管内的生殖细胞均表达PITX2。所有证据表明，PITX2的差异表达可能与性别特异性的胚胎期和出生后性腺发育以及生理过程有关。
