Estrogen is a key regulator in the development of the female reproductive system. It also stimulates oviduct development in immature chicks. We identified candidate genes and pathways associated with the development of chicken oviducts. A pellet containing the synthetic estrogen analog diethylstilbestrol (DES) was implanted subcutaneously in 1-wk-old female chicks for 10 days. The pellet was removed from half the group for 10 days, and an additional dose was given for a further 10 days. Total RNA was extracted from the oviducts of DES-treated and untreated chicks and subjected to an Affymetrix chicken GeneChip analysis. We found differential expression of 2290 and 1745 transcripts from the oviducts that were treated with DES once and twice, respectively. We also found a twofold or greater change in the expression of 77 and 390 transcripts between the two control and DES-treated time points, respectively, while we found a change in the expression of 10 transcripts that were common to all groups. Analyses of real-time PCR and in situ hybridization of selected genes confirmed the validity of the gene expression patterns observed in the microarray analysis. In particular, CCRN4L, FAM26F, HAS2, NELF, and NTM were up-regulated in the DES-treated chicken oviducts. High-throughput analysis revealed that the differentially expressed genes were related to tubular formation, epithelial differentiation, hormone interactions, nerve development, and tissue remodeling in the chicken oviduct. This study provides novel insights into candidate genes regulating oviduct development and differentiation via estrogen. The identified genes may serve as biomarkers of reproductive tract development in chicks.

SummaryHuman embryonic stem cells (hESCs) hold great promise for the treatment of many incurable diseases. Sirtuin1 (SIRT1), a class III histone deacetylase, is abundantly expressed in hESCs and is known to regulate early differentiation and telomere elongation. Here, we show that downregulation of SIRT1 promotes cell death in hESCs, but not in differentiated cells, and the SIRT1-inhibition-mediated cell death is preceded by increased DNA damage. This increased DNA damage is at least partially due to decreased levels of DNA repair enzymes such as MSH2, MSH6, and APEX1. Furthermore, SIRT1 inhibition causes p53 activation, which eventually leads to DNA damage-induced apoptosis of hESCs. This study provides valuable insights into the mechanism of SIRT1-mediated hESC survival and should contribute to the development of safe and effective cell therapies.

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Background: The embryonic developmental process in avian species is quite different from that in mammals. The first cleavage begins 4 h after fertilization, but the first differentiation does not occur until laying of the egg (Eyal-Giladi and Kochav (EK) stage X). After 12 to 13 h of incubation (Hamburger and Hamilton (HH) stage 3), the three germ layers form and germ cell segregation in the early chick embryo are completed. Thus, to identify genes associated with early embryonic development, we compared transcript expression patterns between undifferentiated (stage X) and differentiated (HH stage 3) embryos.

ObjectiveThis study was conducted to compare morphological defects, viability, motility (MOT), fertility (F), and hatchability (H) in four Korean native chicken breeds (KNCBs), and to evaluate whether defective segments of spermatozoa are associated with MOT, F, and H.MethodsFour KNCBs, including Korean Ogye (KO), Hwangbong (HB), Hyunin Black (HH), and Hoengseong Yakdak (HY) were used. White Leghorn (WL) was used as a control. Nine cocks from each breed were randomly assigned into three groups. Semen was collected by abdominal massage method. Eosin-nigrosin staining method was used to identify live-dead spermatozoa. Different segments and specific morphological defects of spermatozoa were identified using 4′, 6-diamidino-2-phenylidole and MitoTracker Red CMXRos. F and H rates were evaluated following artificial insemination (AI).ResultsKO had the highest MOT rate compared to HY. Viable normal sperm rates of KO and HH were high and comparable with WL. HY spermatozoa had the highest viable abnormal sperm (VAS) or morphological defect rate followed by HB. Likewise, HB spermatozoa had the highest dead sperm (dead) rate compared to KO, HY, and WL. Bent, coiled, detached, broken, and knotted were common identified specific morphological defects for all breeds. Most morphological defects were at the head and tail in all breeds. VAS showed strong negative correlation with MOT (r = −0.697) and F (r = −0.609). Similarly, defective tail was negatively correlated with MOT (r = −0.587), F (r = −0.797), and H (r = −0.448). The F and H rates of KO and WL were comparable.ConclusionThese data indicate that most identified specific morphological defects are at the head and tail. VAS and defective tail were associated with poor motility, F, and H. KNCBs showed more morphological defects than WL. Finally, these results will facilitate successful AI and semen cryopreservation.