Quantitative Analysis of Cell Allocation During Liver Development, Using the spfash-Heterozygous Female Mouse

Abstract

Mosaicism of ornithine transcarbamylase (OTC) expression in hepatocytes was quantitatively analyzed during liver development of the spf(ash)-heterozygous female mouse. Because the mosaic patterns depend on cell migration and cell mixing, such analysis could give insights on the growth pattern or allocation pattern of hepatocytes during liver development. Complex mosaic patterns of OTC-positive and -negative hepatocytes were observed in sections of fetal and postnatal livers. Sizes of patches, which were aggregates of OTC-positive or -negative hepatocytes, increased during development. Patches were slender and comparatively simple in 15.5- and 17.5-day fetal and neonatal livers. Quantitative analysis of patch shapes demonstrated that undulation of patches was maximal at 7 postnatal days. Patches with nodular shapes also started to increase in number at this stage. Isolated patches in sections of fetal livers and postnatal livers three-dimensionally connected with one another. However, especially in fetal livers, in which OTC-positive patches were minor, due to the presence of abundant hemopoietic cells, isolated three-dimensional patches consisting of approximately 5 to 70 cells were often found. They were shaped like slender branching or zigzag-shaped cords, but no definite orientation such as portal-central was observed in them at any stage. These results suggest that hepatocytes contiguously allocate their daughter cells as zigzag-shaped or branching cords at younger stages. Some hepatocytes grow with nodular formation after 7 postnatal days. Migration and mixing of hepatocytes appear to be more extensive at fetal stages than in the adult liver. Immunohistochemical analysis of intercellular junction proteins (E-cadherin, connexins 26 and 32, occludin, and ZO-1) also revealed that their expression and distribution changed in hepatocytes during development, which may be correlated with the OTC mosaic patterns.

Cell Lineage Analysis during Liver Development Using the spfash-Heterozygous Mouse

“…Therefore, there may be no special zones for growth of hepatoblasts in the liver parenchyma before 15.5 days of gestation. This conclusion agrees well with findings of the random allocation of progeny by hepatocytes during postnatal liver develop- (Iannaccone et al, 1987;Khokha et al, 1994;Ng and Iannaccone, 1992;Shiojiri et al, 2000).…”

“…As discussed elsewhere (Shiojiri et al, 2000), they might correspond to hepatoblast clones. These could be observed because of the high imbalance of OTCpositive hepatoblasts in fetal livers in which hemopoiesis was climaxing.…”

Assessing the role of hematopoietic plasticity for endothelial and hepatocyte development by non-invasive lineage tracing

“…Together, these observations suggest that even the earliest hematopoietic to hepatocyte contributions should have been detected in the vav ancestry model. The number of hepatocytes increases ~100 fold between E13.5 and adulthood (Anzai et al, 2003;Wang et al, 2002), resulting in a liver that is a mosaic of clonally derived colonies (Kennedy et al, 1995;Shiojiri et al, 2000), as can also be seen in chimeric control mice ( Fig. 2A).…”

CASK Deletion in Intestinal Epithelia Causes Mislocalization of LIN7C and the DLG1/Scrib Polarity Complex without Affecting Cell Polarity

“…The intestinal epithelium is particularly amenable to mosaic analysis because it undergoes continual, rapid self-renewal while maintaining a precise spatiotemporal organization. Mosaicism driven by X inactivation has been visualized in the murine intestine through histochemical detection of two X-linked enzymes in heterozygous females (Griffiths et al, 1988;Shiojiri and Mori, 2003). In this previous work, X-linked gene expression was used as a marker to identify clonal patches of epithelium.…”

“…This is evidenced by the finding that in adult CASK ϩ/Ϫ mosaic mice CASK-deficient crypts comprise only ϳ15% of the total crypt number. In rodents, crypt morphogenesis occurs during the first postnatal week, and with respect to X inactivation, crypts rapidly become homogeneous (Shiojiri and Mori, 2003). During subsequent growth of the animal and in response to inflammation and/or injury, crypts replicate by a process termed crypt fission (Yen and Wright, 2006).…”