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B-cell Translocation Gene 2: Expression in the Rat Ovary and Potential Association with Adenine Nucleotide Translocase 2 in Mitochondria. Park JI et al. The B-cell translocation gene 2 (Btg2) is an anti-proliferative tumor suppressor gene that behaves as a transcriptional regulator. The present study investigated gonadotropin induction of Btg2 in the rat ovary and the mechanism of Btg2 action as a partner of mitochondrial protein adenine nucleotide translocase 2 (Ant2). Transient induction of Btg2 as well as Btg1 mRNA levels by LH/hCG was observed in ovarian granulosa cells. Btg2 protein levels were also stimulated by LH/hCG. LH-induced gene expression of Btg2 required ERK signal pathway. Studies of deletion mutants in HeLa cells showed that deletion of Btg2 C-terminus (Btg2/?C) abolished the interaction with Ant2. In fact, the expression levels of Btg2/?C construct were decreased in mitochondrial fraction. Btg2 was also expressed in mitochondria and interacted with Ant2 in preovulatory granulosa cells. Interestingly, a Btg2/?C construct inhibited an action of Btg2 wild-type on ATP and H(2)O(2) production. These findings demonstrate the gonadotropin stimulation of Btg2 in the ovary and, the physical interaction of Btg2 with Ant2 in mitochondria.
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.
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