NCBI Summary:
The protein encoded by this gene is a member of the STAT protein family. In response to cytokines and growth factors, STAT family members are phosphorylated by the receptor associated kinases, and then form homo- or heterodimers that translocate to the cell nucleus where they act as transcription activators. This protein can be activated by various ligands including interferon-alpha, interferon-gamma, EGF, PDGF and IL6. This protein mediates the expression of a variety of genes, which is thought to be important for cell viability in response to different cell stimuli and pathogens. Two alternatively spliced transcript variants encoding distinct isoforms have been described. [provided by RefSeq]
General function
Transcription factor
Comment
Cellular localization
Cytoplasmic, Nuclear
Comment
Ovarian function
Follicle atresia
Comment
Effects of signal transducer and activator of transcription (STAT) genes STAT1 and STAT3 genotypic combinations on fertilization and embryonic survival rates in Holstein cattle. Khatib H et al. Infertility is a major cause of dairy cow culling and economic loss. Signal transducer and activator of transcription (STAT) proteins are transcription factors that play an important role in fertility and early embryonic development, among many other functions. Previous studies have reported the association of several genes from the JAK/STAT signaling pathway with fertility traits in cattle. The STAT1 and STAT3 genes are members of this pathway and are known to interact with each other by forming a heterodimer complex that enters the nucleus and controls expression of specific genes. Thus, the objective of this study was to investigate the effects of the interactions between polymorphisms in these genes on fertilization and early embryonic survival rates using an in vitro fertilization system. A total of 7,519 oocytes, collected from 445 ovaries, were exposed to sperm and a total of 5,075 embryos were produced. Fertilization rate was calculated as the number of cleaved embryos at 48 h post-fertilization out of the total number of oocytes exposed to sperm. Early embryonic survival rate of embryos was calculated as the number of blastocysts on d 7 of development out of the total number of embryos cultured. Effects of ovary genotypes on fertilization and early embryonic survival rates were evaluated. Single-SNP analysis revealed a statistically significant association between SNP25402 in STAT3 and fertilization rate. Oocytes produced from ovaries with AA genotype showed a 0.701 fertilization rate versus 0.666 and 0.663 for oocytes produced from AC and CC ovaries, respectively. The interaction between STAT3 SNP (SNP19069/SNP25402) was highly significant for survival rate but not for fertilization rate. Also, the interaction between STAT1 SNP and SNP19069 was highly significant for survival rate. Genotype combinations found to promote fertilization and embryonic survival could be incorporated into breeding programs aimed at improving fertility performance in dairy cattle.
Expression regulated by
Growth Factors/ cytokines, ghrelin
Comment
Involvement of the transcription factor STAT-1 in the regulation of porcine ovarian granulosa cell functions treated and not treated with ghrelin. Benco A et al. The aim of our in vitro experiments was to study the role of the transcription factor STAT-1 and the hormone ghrelin in controlling porcine ovarian function. The effects of treatment with ghrelin (0, 1, 10, 100 ng/ml), transfection-induced overexpression of transcription factor STAT-1, and their combination on apoptosis (expression of apoptosis-related peptides caspase-3, Bax and anti-apoptotic peptide Bcl-2), proliferation (expression of proliferating cell nuclear antigene PCNA, proliferation-associated protein kinase MAPK/ERK1, 2) and release of the hormones progesterone (P4), prostaglandin F (PGF) and oxytocin (OT) by cultured porcine ovarian granulosa cells was evaluated using RIA, immunocytochemistry and SDS PAGE-Western immunoblotting. The obtained results suggest that (1) ghrelin directly affects porcine ovarian cells function - stimulates proliferation, inhibits apoptosis and affects secretory activity. Furthermore they demonstrated (2) the involvement of the transcription factor STAT-1 in controlling these functions: the promotion of some markers of apoptosis (Bax), inhibition of some markers of proliferation (MAPK/ERK1,2) and stimulation of PGF release. Finally, (3) the obtained data failed to demonstrate that STAT-1 is involved in mediating the action of ghrelin on ovarian cell functions.
Ovarian localization
Ovarian tumor
Comment
MMTV-neu mice deficient in STAT1 are susceptible to develop ovarian teratomas. Hannesdttir L et al. Signal transducer and activator of transcription 1 (STAT1) serves in the protection of the organism against pathogens and other harmful insults. It is implicated in innate immune response, immunosurveillance, tumor-suppression, and the response to genotoxic as well as oxidative stress. We report here that 9 of 140 examined STAT1 deficient mouse mammary tumor virus-neu (MMTV-neu) mice developed differentiated ovarian teratomas, which histologically resemble benign dermatoid cysts. Conventional karyotyping revealed diploidy without structural rearrangements of the chromosomes. STAT1 proficient MMTV-neu mice with the same genetic background (FVB/N), and STAT1 deficient C57BL/6 mice failed to develop this type of tumor. This indicates that STAT1 deficiency promotes teratoma formation and this depends on MMTV-neu expression and/or the genetic background. Since ovarian teratomas are considered to develop as a consequence of alterations in the maturation of oocytes and follicular cells, we compared the ovaries from non-tumor bearing STAT1 deficient and proficient MMTV-neu mice. No detectable alterations in the number and proportion of the different follicular developmental stages were detected, implying the absence of non-redundant functions of STAT1 in normal folliculogenesis, as well as in follicular atresia. However, strong staining for STAT1 was detectable in granulosa and theca cells. These results point to a role for STAT1 in protecting from teratoma formation in a later step of tumorigenesis, e.g. by inducing apoptosis and eliminating premature or aberrantly formed follicles which have the potential to transform into teratomas.