NCBI Summary:
This gene encodes a member of the annexin family. Members of this calcium-dependent phospholipid-binding protein family play a role in the regulation of cellular growth and in signal transduction pathways. This protein functions as an autocrine factor which heightens osteoclast formation and bone resorption. This gene has three pseudogenes located on chromosomes 4, 9 and 10, respectively. Multiple alternatively spliced transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jul 2008]
Characterization of annexin A2 in chicken follicle development: Evidence for its involvement in angiogenesis. Zhu G et al. (2015) Annexin A2 (ANXA2) is a calcium-dependent, phospholipid-binding protein found in various cells and tissues. ANXA2 plays multiple roles in regulating cellular functions and is often over-expressed in different types of tumors including ovarian cancer. Others and we previously found that ANXA2 was up-regulated in the ovaries of hens with higher laying rate, indicated that ANXA2 is involved in avian follicle development. In this study, we found that ANXA2 mRNA expression increased during chicken ovary maturation and follicle development. In the pre-ovulatory follicles, ANXA2 expression level was significantly higher in theca cells than granulosa cells. In theca cells, ANXA2 expression could be stimulated by follicle-stimulating hormone (FSH) and estrogen but not luteinizing hormone (LH) or progesterone. The core promoter regions control the basal and FSH-induced ANXA2 gene expression were identified. Forced expression of ANXA2 could induce the expression of angiogenic factors and receptors in theca cells. Furthermore, ANXA2 overexpression resulted increased vascular endothelial growth factor A (VEGFA) secretion and theca cell proliferation. Current study not only provides the first evidence of expression and regulation of ANXA2 in chicken ovary, but also suggests that ANXA2 is involved in follicular angiogenesis and contributes to successful follicle development and ovulation.//////////////////
Identification of metaphase II-specific gene transcripts in porcine oocytes and their expression in early stage embryos Cui XS, et al .
Annealing control primer (ACP)-based GeneFishing polymerase chain reaction (PCR) was used to identify the genes that are specifically or prominently expressed in porcine oocytes at the metaphase II (MII) and germinal vesicle (GV) stages. By using 60 ACPs, 13 differentially expressed genes (DEGs) were identified. The cloned genes or expressed sequence tags (ESTs) showed sequence similarity with known genes or ESTs of other species in GenBank. The mRNA expression during oocyte maturation and early embryonic development in both pigs and mice of four of these genes (namely transcription factor TZP, annexin A2, hypoxia-inducible protein 2, and ATPase 6) was further characterised by real-time quantitative reverse transcription-PCR. All four genes were markedly upregulated in pig and mouse MII oocytes compared with GV-stage oocytes. The expression levels of the four genes decreased gradually during early cleavage. Thus, these genes may play important roles during oocyte maturation and/or early cleavage in mammals. Although the detailed functions of these genes remain to be determined, their identification in the present study provides insights into meiotic maturation and fertilisation.
Expression regulated by
LH
Comment
Gene expression increased. Luteinization of porcine preovulatory follicles leads to systematic changes in follicular gene expression. Agca C et al. The LH surge initiates the luteinization of preovulatory follicles and causes hormonal and structural changes that ultimately lead to ovulation and the formation of corpora lutea. The objective of the study was to examine gene expression in ovarian follicles (n = 11) collected from pigs (Sus scrofa domestica) approaching estrus (estrogenic preovulatory follicle; n = 6 follicles from two sows) and in ovarian follicles collected from pigs on the second day of estrus (preovulatory follicles that were luteinized but had not ovulated; n = 5 follicles from two sows). The follicular status within each follicle was confirmed by follicular fluid analyses of estradiol and progesterone ratios. Microarrays were made from expressed sequence tags that were isolated from cDNA libraries of porcine ovary. Gene expression was measured by hybridization of fluorescently labeled cDNA (preovulatory estrogenic or -luteinized) to the microarray. Microarray analyses detected 107 and 43 genes whose expression was decreased or increased (respectively) during the transition from preovulatory estrogenic to -luteinized (P<0.01). Cells within preovulatory estrogenic follicles had a gene-expression profile of proliferative and metabolically active cells that were responding to oxidative stress. Cells within preovulatory luteinized follicles had a gene-expression profile of nonproliferative and migratory cells with angiogenic properties. Approximately, 40% of the discovered genes had unknown function.
Ovarian localization
Oocyte, Granulosa, Theca
Comment
Changes in mouse granulosa cell gene expression during early luteinization. McRae RS et al. Changes in gene expression during granulosa cell luteinization have been measured using serial analysis of gene expression (SAGE). Immature normal mice were treated with pregnant mare serum gonadotropin (PMSG) or PMSG followed, 48 h later, by human chorionic gonadotropin (hCG). Granulosa cells were collected from preovulatory follicles after PMSG injection or PMSG/hCG injection and SAGE libraries generated from the isolated mRNA. The combined libraries contained 105,224 tags representing 40,248 unique transcripts. Overall, 715 transcripts showed a significant difference in abundance between the two libraries of which 216 were significantly down-regulated by hCG and 499 were significantly up-regulated. Among transcripts differentially regulated, there were clear and expected changes in genes involved in steroidogenesis as well as clusters of genes involved in modeling of the extracellular matrix, regulation of the cytoskeleton and intra and intercellular signaling. The SAGE libraries described here provide a base for functional investigation of the regulation of granulosa cell luteinization.
Changes in mouse granulosa cell gene expression during early luteinization. McRae RS et al. Changes in gene expression during granulosa cell luteinization have been measured using serial analysis of gene expression (SAGE). Immature normal mice were treated with pregnant mare serum gonadotropin (PMSG) or PMSG followed, 48 h later, by human chorionic gonadotropin (hCG). Granulosa cells were collected from preovulatory follicles after PMSG injection or PMSG/hCG injection and SAGE libraries generated from the isolated mRNA. The combined libraries contained 105,224 tags representing 40,248 unique transcripts. Overall, 715 transcripts showed a significant difference in abundance between the two libraries of which 216 were significantly down-regulated by hCG and 499 were significantly up-regulated. Among transcripts differentially regulated, there were clear and expected changes in genes involved in steroidogenesis as well as clusters of genes involved in modeling of the extracellular matrix, regulation of the cytoskeleton and intra and intercellular signaling. The SAGE libraries described here provide a base for functional investigation of the regulation of granulosa cell luteinization.