WormBase Tree Display for Expr_pattern: Expr12892

Expr12892 Expression_of: Gene: WBGene00003397
    Reflects_endogenous_expression_of: WBGene00003397
  Expression_data: Anatomy_term: WBbt:0005175 Certain
      WBbt:0005733 Certain
      WBbt:0005735 Certain
      WBbt:0005741 Certain
      WBbt:0006748 Certain
    GO_term: GO:0005886
      GO:0005737
  Type: Reporter_gene
  Pattern: Variable MOM-5::GFP expression from the zuIs145 transgene was observed in many larval cells, including cells of the gonad, vulva, tail, nervous system, and hypodermis. At about 5 hr after hatching, MOM-5::GFP was prominent in lateral skin cells called V1 through V6 and T, and in a neuroblast called QL. In each of these cells, MOM-5::GFP was present as apparently random puncta on, or near, the cell surface and in the cytoplasm. When the transgenes were crossed into otherwise wild-type embryos, only faint, or no, expression of MOM-5::GFP was detectable before the AB32 stage by fluorescence microscopy or by staining with an antiserum for GFP. When visible, MOM-5::GFP appeared dispersed throughout the cytoplasm and was not noticeably associated with the cell membrane or cortex. The low level of MOM-5::GFP may mean that the protein is expressed but unstable in early embryos or that high levels of early expression were selected against in the initial generation of transgenic animals. The level of MOM-5::GFP increased markedly in most cells beginning at the AB32 stage and persisted until late in embryogenesis. Within expressing cells, MOM-5::GFP was present in a diffuse distribution throughout the cytoplasm and was enriched on or near the cell plasma membrane. In addition, MOM-5::GFP often was enriched in prominent cytoplasmic puncta. Costaining experiments showed that these puncta were closely associated with, but distinct from, centrosomes. These puncta may correspond to large secretory vesicles; however, their positions are noteworthy because MOM-5 has an essential role in determining centrosome position/spindle axis for certain embryonic blastomeres. Most cells showed comparable levels of membrane-associated MOM-5::GFP, with the following exceptions. First, the descendants of the embryonic founder blastomeres called E and C reproducibly showed less MOM-5::GFP expression than other cells. Second, postmitotic epidermal cells (ventral hypodermal cells) that spread across and enclose the ventral surface of the embryo showed a transient enrichment of MOM-5::GFP at their actin-rich leading edges. Finally, several embryos contained small groups of cells of variable identity with exceptionally high levels of MOM-5::GFP; because similar levels of expression were not observed in the same cells in other embryos at the same stage, the authors consider this a likely artifact of transgene expression. Several embryos that were costained for both GFP and POP-1 also showed exceptionally high levels of MOM-5::GFP expression in one or more groups of cells of variable identity. Although MOM-5::GFP appeared to be distributed uniformly along the membranes of most cells throughout the cell cycle, cells in prophase occasionally showed a slight enrichment of MOM-5::GFP toward the posterior pole. Cells in late prophase showed a small but consistent enrichment of MOM-5::GFP toward their posterior pole. MOM-5::GFP appeared to localize to the posterior pole approximately 3-5 min before cell division. This transient asymmetry resulted in the posterior daughter inheriting slightly more MOM-5::GFP than the anterior daughter. The a/p asymmetry in MOM-5::GFP distribution was reiterated in daughter cells monitored through successive cell divisions. MOM-5::GFP asymmetry was most apparent in dividing cells on the surface of the embryo, but could also be detected in internal cells such as those forming the pharyngeal primordium. MOM-5::GFP asymmetry was visible in the divisions of about 80% of the surface cells analyzed (n=152), and in all cases MOM-5::GFP was enriched toward the posterior pole. Although MOM-5::GFP often was distributed across the entire posterior surface of a dividing cell, in many cases it appeared to be concentrated into a distinct posterior focus prior to division.
  Picture: WBPicture0000014011
    WBPicture0000014012
  Reference: WBPaper00024672
  Transgene: WBTransgene00005238
    WBTransgene00006414