Follicle-stimulating hormone regulates pro-apoptotic protein Bcl-2-interacting mediator of cell death-extra long (BimEL)-induced porcine granulosa cell apoptosis.

The pro-apoptotic protein Bim (B-cell lymphoma-2 (Bcl-2)-interacting modulator of cell death) has recently been identified and shown to promote cell death in response to several stimuli. In this report, we investigated the role of Bim in porcine follicular atresia. Initially, Bim cDNA was cloned and characterized from porcine ovarian tissue. Porcine Bim had three alternative splicing variants (Bim-extra long, Bim-long, and Bim-short), all containing the consensus Bcl-2 homology 3 domain. We then found the Bim-extra long (Bim(EL)) protein, the most abundant isoform of Bim, was strongly expressed and co-localized with apoptotic (TUNEL-positive) granulosa cells from porcine atretic follicles. Furthermore, overexpression of Bim(EL) triggered apoptosis in granulosa cells. In primary granulosa cell cultures under basal conditions, we observed that Bim(EL) expression was dampened by treatment with follicle-stimulating hormone (FSH). The role of the PI3K/Akt pathway in the regulation of repression was clarified by the use of the PI3K inhibitor, LY294002, and by transfection with Akt siRNA. Forkhead Box Protein O3a (FoxO3a), a well defined transcriptional activator of Bim, was phosphorylated at Ser-253 and inactivated after FSH stimulation. Also, FSH abolished FoxO3a nuclear accumulation in response to LY294002. Finally, chromatin immunoprecipitation assays demonstrated that FoxO3a directly bound and activated the bim promoter. Taken together, we conclude that Bim(EL) induces porcine granulosa cell apoptosis during follicular atresia, and its expression is regulated by FSH via the PI3K/Akt/FoxO3a pathway.

[Mapping QTLs controlling vascular bundle and panicle-related traits from Yuanjiang common wild rice (Oryza rufipogon Griff.)].

An advanced backcross population (BC3F2), derived from the cross between Yuanjiang common wild rice as the donor parent and Teqing as recurrent parent, was used to map QTLs controlling the number of vascular bundle and panicle-related traits from Yuanjiang common wild rice. Seven QTLs controlling the number of large vascular bundles in peduncle were detected on chromosome 1, 2, 3, 4, 7 and 10. Five QTLs for the number of small vascular bundles in peduncle were mapped on chromosome 1, 2, 3, 4 and 8. A total of 15 QTLs for the number of primary and secondary rachis branches and spikelets per panicle were identified on all chromosomes except chromosome 11 and 12. Most of alleles derived from O. rufipogon Griff. showed negative effect that reduced significantly vascular bundle, rachis branches and spikelets per panicle, suggesting that during the evolution from common wild rice to cultivated rice, favorable alleles were retained while removed undesirable ones. Most of QTLs controlling vascular bundle, rachis branches and spikelets per panicle showed cluster form or close linkage on chromosomes. The directions of their additive effects were consistent, which explained the genetic basis of significant correlation of their phenotypic characters. All the information suggested parallel evolution relationship among these traits.

[Identification of quantitative trait loci controlling plant height and days to heading from Yuanjiang common wild rice (Oryza rufipogon Griff.)].

An advanced backcross strategy was used to identify quantitative trait loci (QTLs) associated with plant height and days to heading in the BC3F2 population derived from an accession of common wild rice (Oryza rufipogon Griff.) from Yuanjiang in Yunnan Province of China, as the donor, and an elite Indica cultivar "Teqing", as the recipient. Based on analyses of 116 SSR markers distributed throughout the rice genome and by using single-point analysis, four putative QTLs derived from O. rufipogon were detected for plant height on chromosome 1, and 6 QTLs for days to heading on chromosome 1, 3, 7, 8 and 11. All Alleles of QTLs for plant height from O. rufipogon could increase plant height of the backcross population. One QTL near RM104 on chromosome 1, explaining 27% and 28% of phenotypic variance and additive value reached 26.24 cm and 26.28 cm respectively in Beijing and Hefei, was detected. The location of this QTL is corresponding to sd-1. One QTL near the marker RM25 on chromosome 1, explaining 13% and 15% of phenotypic variance was identified. The additive value of this QTL reached 4.60 days and 3.65 days respectively in Beijing and Hefei, and the allele from O. rufipogon could delay the backcross population's days to heading.