. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 228 W. R. BATES Table HI Distribution ofp58 in i compressed eight-celled embryos Maximum number of blastomeres per embryo stained with NN18 antibody Specimens 0 1 5678 Normal embryos 22240 0 0000 Compressed embryos 31 I 0 22* 0 0 0 0 * In five embryos, five or six blastomeres were in the plane of section. oplasmin-Cl may be the cytoskeletal scaffold that an- chors muscle cell determinants. The expression of a muscle actin promoter-/ac'Z re- porter gene construct, MocuM A1 /lacZ, was recently ex- amined in the tailless larvae
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. 228 W. R. BATES Table HI Distribution ofp58 in i compressed eight-celled embryos Maximum number of blastomeres per embryo stained with NN18 antibody Specimens 0 1 5678 Normal embryos 22240 0 0000 Compressed embryos 31 I 0 22* 0 0 0 0 * In five embryos, five or six blastomeres were in the plane of section. oplasmin-Cl may be the cytoskeletal scaffold that an- chors muscle cell determinants. The expression of a muscle actin promoter-/ac'Z re- porter gene construct, MocuM A1 /lacZ, was recently ex- amined in the tailless larvae of Molgula occult a. In these larvae, which lack p58 and do not develop functional muscle cells, low levels of /i-galactosidase activity were detected in a few posterior cells (Kusakabe el ai. 1996). This result and the presence of insertions, deletions, and codon substitutions in the coding regions of orthologous larval muscle actin genes isolated from the urodele spe- cies Molgula oculata suggest that mutations in muscle genes rather than changes in trans-acting regulatory fac- tors are responsible for the regression of muscle cells. These investigators also reported that MocuMAl//acZ constructs are expressed in mesenchyme and other non- muscle cell types in urodele larvae and that the M. oc- culta cells expressing /3-galactosidase activity did not cor- respond to the cells expressing low levels of vestigial AchE activity. Therefore, these results suggest that the activity of the MocuM A1 promoter is somewhat "leaky" in some cell types, as is the transcription of AchE genes in vestigial muscle cells of several anural ascidian species (Whittaker, 1979; Jeffery and Swalla, 1990b; and Bates and Mallett, 1991). The results obtained by Jeffery and Meier (1983), Swalla el ai (1991), Nishikata and Wada (1996) and those reported in the present study suggest that determinants associated with the myoplasmic cy- toskeleton are required for the normal promoter activi- ties of
Size: 1801px × 1388px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
