A SET/MYND chromatin re-modelling protein regulates Dictyostelium prespore patterning

SmdA is a Dictyostelium orthologue of the SET/MYND chromatin re-modelling proteins. In developing structures derived from a null mutant for smdA (a smdA- strain), prestalk patterning is normal, but using a prespore lacZ reporter fusion, there is ectopic accumulation of β-galactosidase in the prestalk region. As wild type slugs migrate, there is continual forward movement and re-differentiation of prespore cells into prestalk cells. Thus, a potential explanation for the ectopic reporter localization in smdA null prestalk cells is an increased rate of re-differentiation and anterior movement of prespore cells. In support of this notion, analysis of an unstable lacZ reporter, driven by the prespore promoter, reveals a normal staining pattern in the smdA- strain. We suggest that one or more genes regulated by SmdA acts to repress prespore re-specification

Effect of the luteinizing hormone on embryo production in superovulated rabbit does

peer reviewedaudience: researcher, professional, student, popularizationFor most domestic animals, the responses to superovulation treatments are not controlled as a consequence of the lack of knowledge on exogenous gonadotrophins effects on the ovarian function. The role of luteinizing hormone (LH) on the number and quality of embryos produced was evaluated on rabbit does superovulated with porcine FSH (pFSH). Parameters of embryos recovery, in vitro and in vivo embryo development rates after freezing/thawing were compared. We used three experimental groups: (1) control group without superovulation treatment, (2) "pFSH + pLH" and (3) "pFSH" groups where females were treated with pFSH, respectively, with (20%) or without (0%) porcine LH supplementation. The number of corpora lutea and the number of embryos produced were significantly higher (p < 0.001) in superovulated does than in control group (27.1, 26.7 versus 11.9 corpora lutea and 20.3, 21.2 versus 9.6 embryos produced for pFSH + pLH, pFSH and control group, respectively). However, both gonadotrophins administrations (groups 2 and 3) led to defaults of ovulation when compared with untreated does. No significant difference was observed between the number and quality of the embryos produced by does treated with pFSH + pLH or with pFSH alone. Moreover, we observed no significant difference between results of in vivo and in vitro viability assays after thawing. We concluded that pFSH alone seems to be sufficient to stimulate the follicles growth and that exogenous pLH administrated has no effect on the quantity and quality of embryos. Further studies are needed to evaluate the hormonal patterns before and after the gonadotrophins injections in the rabbit species. (c) 2007 Elsevier Inc. All rights reserved