Uterine dysfunction and genetic modifiers in centromere protein B-deficient mice
GENOME RESEARCH
Authors: Fowler, KJ; Hudson, DF; Salamonsen, LA; Edmondson, SR; Earle, E; Sibson, MC; Choo, KHA
Abstract
Centromere protein B (CENP-B) binds constitutively to mammalian centromere repeat DNA and is highly conserved between humans and mouse. Cenpb null mice appear normal but have lower body and testis weights. We demonstrate here that testis-weight I eduction is seen in male null mice generated on three different genetic backgrounds (denoted R1, W9.5, and Cn), whereas body-weight reduction is dependent on the genetic background as well as the gender of the animals. In addition, Cenpb null females show 31%, 33%, and 44% reduced uterine weights on the RI, W9.5, and C57 backgrounds, respectively. Production of "revertant" mice lacking the targeted frameshift mutation but not the other components of the targeting construct corrected these differences, indicating that the observed phenotype is attributable to Cenpb gene disruption rather than a neighbouring gene effect induced by the targeting construct. The R1 and W9.5 Cenpb null Females are reproductively competent but show age-dependent reproductive deterioration leading to a complete breakdown at or before 9 months of age. Reproductive dysfunction is much more severe in the C57 background as Cenpb null females are totally incompetent or are capable of producing no more than one litter. These results implicate a further genetic modifier effect on female reproductive performance. Histology of the uterus reveals normal myometrium and endometrium but grossly disrupted luminal and glandular epithelium. Tissue in situ hybridization demonstrates high Cenpb expression in the uterine epithelium of wild-type animals. This study details the first significant phenotype of Cenpb gene disruption and suggests an important role of Cenpb in uterine morphogenesis and function that may have direct implications for human reproductive pathology.
Subcellular localization of poly(ADP-ribose) glycohydrolase in mammalian cells
BIOCHEMICAL AND BIOPHYSICAL RESEARCH COMMUNICATIONS
Authors: Ohashi, S; Kanai, M; Hanai, S; Uchiumi, F; Maruta, H; Tanuma, S; Miwa, M
Abstract
Posttranslational modification plays important roles in a range of cellular functions. Poly(ADP-ribosyl)ation influences DNA repair, transcription, centrosome duplication, and chromosome stability. Poly(ADP-ribose) attached to acceptor proteins should be properly hydrolyzed by poly(ADP-ribose) glycohydrolase (PARG). However the subcellular localization and the role of PARG have not been well characterized. Here, we transiently expressed GFP- or Myc-tagged human PARG in mammalian cells and revealed that the subcellular distribution of human PARG changes dramatically during the cell cycle. GFP-hPARG is found almost exclusively in the nucleus during interphase. During mitosis, most GFP-hPARG protein localizes to the cytoplasm and hardly any GFP-hPARG protein is found associated with the chromosomes. Furthermore, we found that GFP-hPARG localizes to the centrosomes during mitosis. Our findings suggest that shuttling of PARG between nucleus and cytoplasm and proper control of poly(ADP-ribose) metabolism throughout the cell cycle may play an important role in regulating cell cycle progression and centrosome duplication. (C) 2003 Elsevier Inc. All rights reserved.