Guocheng Lan

Publications (34) View all

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  Available from: Guocheng Lan

  Article: MPF governs the assembly and contraction of actomyosin rings by activating RhoA and MAPK during chemical-induced cytokinesis of goat oocytes.

  Yan-Guang Wu, Ping Zhou, Guo-Cheng Lan, Da Gao, Qing Li, De-Li Wei, Hui-Li Wang, Jing-He Tan
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  ABSTRACT: The interplay between maturation-promoting factor (MPF), mitogen-activated protein kinase (MAPK) and Rho GTPase during actin-myosin interactions has yet to be determined. The mechanism by which microtubule disrupters induce the formation of ooplasmic protrusion during chemical-assisted enucleation of mammalian oocytes is unknown. Moreover, a suitable model is urgently needed for the study of cytokinesis. We have established a model of chemical-induced cytokinesis and have studied the signaling events leading to cytokinesis using this model. The results suggested that microtubule inhibitors activated MPF, which induced actomyosin assembly (formation of ooplasmic protrusion) by activating RhoA and thus MAPK. While MAPK controlled actin recruitment on its own, MPF promoted myosin enrichment by activating RhoA and MAPK. A further chemical treatment of oocytes with protrusions induced constriction of the actomyosin ring by inactivating MPF while activating RhoA. In conclusion, the present data suggested that the assembly and contraction of the actomyosin ring were two separable steps: while an increase in MPF activity promoted the assembly through RhoA-mediated activation of MAPK, a decrease in MPF activity triggered contraction of the ring by activating RhoA.
  PLoS ONE 01/2010; 5(9):e12706. · 4.09 Impact Factor
• Chapter: The Generation of Transgenic Mice Expressing Human Antibody Repertoires

  Xiangang Zou, Guocheng Lan, Michael J. Osborn, Marianne Brüggemann
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  ABSTRACT: Introduction of exogenous genes into the mouse germline, even followed by tissue specific expression, has been achieved for many transgenes. In addition, gene targeting in embryonic stem cells has silenced undesirable loci. Although several companies offer the production of transgenic mice by DNA microinjection and/or embryonic stem (ES) cell manipulation, only partial information is available regarding preparative methodologies. Here we provide detailed protocols, all routinely used in our laboratories, of DNA purification, ES cell maintenance and the introduction of large gene loci on yeast artificial chromosomes (YACs) into ES cells by protoplast fusion. These methods resulted in transgenic and knock-out animals and several mouse strains with single authentic copies of a human Ig loci integrated randomly in a mouse chromosome; the largest region being over 1000 kb.
  12/2009: pages 235-254;
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  Article: The Rapidity of In Vitro Maturation of Goat Oocytes Correlates with Follicle Sizes and Affects Blastocyst Development of Cloned Embryos When Used as Recipient Cytoplasts

  Jing-He Tan, Yan-Guang Wu, Guo-Cheng Lan, Zheng-Bin Han, Dong Han, Ping Zhou, Ming-Jiu Luo
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  ABSTRACT: 275 Although it was reported that porcine oocytes that matured rapidlyin vitro were superior in their ability to support developmentof reconstructed embryos, the background for the high developmentalpotential of fast-matured oocytes is
  Biology of Reproduction 01/2009; 81. · 4.01 Impact Factor
• Article: Liquid storage of goat semen in chemically defined extenders.

  C-L Xu, J-B Zhou, B-T Zhao, G-C Lan, M-J Luo, Z-L Chang, H-S Sui, J-H Tan
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  ABSTRACT: The suitability of certain commercial and self-made chemically defined extenders for liquid storage of goat semen was tested and the effects of storage temperatures, dilution rates and sperm washing and pH of extenders on the goat sperm during liquid storage were observed. Semen was collected from nine goat bucks of the Lubei White and Boer breeds using an artificial vagina. Each ejaculate after initial evaluation was diluted with a specific extender, cooled and stored at a desired temperature. Stored semen was evaluated for sperm motility and other parameters every 24 or 48 h of storage. The ranking order of the existing milk- and yolk-free extenders in sustaining goat sperm motility was Androhep > Zorlesco > Beltsville thawing solution > the Tris-glucose medium. The new extender (mZA) which was formulated based on Zorlesco and Androhep was more suitable for goat sperm than Androhep. The mZAP extender with Bovine Serum Albumin (BSA) replaced with polyvinyl alcohol (PVA) worked as efficiently as the mZA in maintaining sperm motility, membrane integrity, acrosome intactness and capacitation status. Goat sperm motility was best maintained at 5 degrees C during liquid preservation, but decreased significantly as the temperature increased. When semen was sixfold diluted, sperm motility was maintained longer (p < 0.05) after centrifugation, but sperm motility did not differ between the centrifuged and non-centrifuged groups when semen was 11-fold diluted. When the extender pH was adjusted from 6.6 to 6.04, the efficiency increased significantly in both Androhep and mZAP. A forward sperm motility of 34% was maintained for 9 days when buck semen was 11-fold diluted and stored at 5 degrees C in mZAP, with pH adjusted to 6.04. It is concluded that for liquid storage of buck semen, the mZA extender was more suitable than other extenders; BSA can be replaced with PVA in mZA; centrifugation to remove seminal plasma can be omitted by adequate dilution; and the storage temperature and pH of extenders affected sperm motility significantly.
  Reproduction in Domestic Animals 11/2008; 44(5):771-8. · 1.36 Impact Factor
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  Article: Pyruvate prevents aging of mouse oocytes.

  Na Liu, Yan-Guang Wu, Guo-Cheng Lan, Hong-Shu Sui, Li Ge, Jun-Zuo Wang, Yong Liu, Tian-Wu Qiao, Jing-He Tan
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  ABSTRACT: Inhibiting oocyte aging is important not only for healthy reproduction but also for the success of assisted reproduction techniques. Although our previous studies showed that cumulus cells accelerated aging of mouse oocytes, the underlying mechanism is unknown. The objective of this paper was to study the effects of pyruvate and cumulus cells on mouse oocyte aging. Freshly ovulated mouse cumulus-oocyte complexes (COCs) or cumulus-denuded oocytes (DOs) were cultured in Chatot-Ziomek-Bavister (CZB) medium or COC-conditioned CZB medium supplemented with different concentrations of pyruvate before being examined for aging signs and developmental potential. Pyruvate supplementation to CZB medium decreased rates of ethanol-induced activation in both COCs and DOs by maintaining their maturation-promoting factor activities, but more pyruvate was needed for COCs than for DOs. Addition of pyruvate to the COC-conditioned CZB also alleviated aging of DOs. Observations on cortical granules, level of BCL2 proteins, histone acetylation, intracellular concentration of glutathione, and embryo development all confirmed that pyruvate supplementation inhibited aging of mouse oocytes. It is concluded that the aging of mouse oocytes, facilitated by culture in COCs, can be partially prevented by the addition of pyruvate to the culture medium.
  Reproduction 06/2009; 138(2):223-34. · 2.58 Impact Factor