Differential expression of non-muscle myosin heavy chain genes during Xenopus embryogenesis

Mech Dev. 1998 Nov;78(1-2):33-6. doi: 10.1016/s0925-4773(98)00136-1.


Class II non-muscle myosins are implicated in diverse biological processes such as cytokinesis, cellularization, cell shape changes and gastrulation. Two distinct non-muscle myosin heavy chain genes have been reported in all vertebrates: non-muscle myosin heavy chain-A (NMHC-A) and -B (NMHC-B). We report here the isolation of the Xenopus homolog of NMHC-A and present a comparative analysis of the developmental and spatial expression patterns of NMHC-A and the previously isolated NMHC-B to address the role of NMHCs in Xenopus development. A 7.5 kb NMHC-A mRNA is present, maternally in unfertilized eggs and throughout embryogenesis, as well as in all adult tissues examined. An additional 8.3 kb zygotic transcript for NMHC-A is also detected, but only during embryonic stages. Whole mount in situ hybridization with tailbud stage embryos shows that NMHC-A mRNA is predominantly expressed in the epidermis, whereas NMHC-B mRNA is expressed in the somites, brain, eyes and branchial arches. Interestingly, the expression of NMHC-B in developing somites is gradually restricted to the center of each somite as differentiation proceeds. DAPI nuclear staining demonstrated that NMHC-B mRNA is colocalized with the nuclei or perinuclear area. In animal cap experiments, treatment with activin A or ectopic expression of Xbra and an activated form of Xlim1 markedly up-regulates NMHC-B as well as muscle actin mRNAs and slightly down-regulates NMHC-A mRNA, consistent with NMHC-B expression in the somitic muscle and NMHC-A expression in the epidermis.

Publication types

  • Comparative Study

MeSH terms

  • Activins
  • Animals
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / physiology
  • Embryo, Nonmammalian / metabolism
  • Fetal Proteins*
  • Gene Expression Regulation, Developmental*
  • Homeodomain Proteins / genetics
  • Homeodomain Proteins / physiology
  • In Situ Hybridization
  • Inhibins / pharmacology
  • LIM-Homeodomain Proteins
  • Myosin Heavy Chains / biosynthesis*
  • Myosin Heavy Chains / genetics
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / physiology
  • Organ Specificity
  • Protein Isoforms / biosynthesis*
  • Protein Isoforms / genetics
  • RNA, Messenger / biosynthesis
  • RNA, Messenger / genetics
  • T-Box Domain Proteins*
  • Transcription Factors / genetics
  • Transcription Factors / physiology
  • Xenopus Proteins*
  • Xenopus laevis / embryology*
  • Xenopus laevis / growth & development
  • Xenopus laevis / metabolism


  • DNA-Binding Proteins
  • Fetal Proteins
  • Homeodomain Proteins
  • LHX3 protein, Xenopus
  • LIM-Homeodomain Proteins
  • Lhx1 protein, Xenopus
  • Nerve Tissue Proteins
  • Protein Isoforms
  • RNA, Messenger
  • T-Box Domain Proteins
  • Transcription Factors
  • Xenopus Proteins
  • Activins
  • Inhibins
  • Myosin Heavy Chains
  • Brachyury protein

Associated data

  • GENBANK/AF055895