title: Spatio-temporal expression of MRF4 transcripts and protein during Xenopus laevis embryogenesis.
abstract: Whereas there have been extensive studies of the expression of XMyf5 and XMyoD during Xenopus embryogenesis, nothing is known about the spatio-temporal accumulation of XMRF4 transcripts and protein. In this report, we describe the cloning and characterization of two full-length MRF4 cDNAs and of their proximal promoters in Xenopus laevis. The comparison of the relative transcript levels of the XMRF4-a and -b genes in developing and adult muscles is highly suggestive of specific functions for the corresponding XMRF4 proteins. Whole-mount embryo in situ hybridization revealed the first XMRF4 transcripts in the more differentiated anterior myocytes of the embryo when the myosin heavy chain E3 mRNA begins to be detectable. XMRF4 mRNA accumulation later extended posteriorly but was never detected in the posterior unsegmented mesoderm, in contrast to XMyoD and XMyf-5. Whole-mount embryo immunohistochemistry revealed that XMRF4 protein accumulated in somite nuclei slightly after XMRF4 transcripts.
authors.affiliation: UMR 7060 CNRS, Equipe Biologie du Développement et de la Différenciation Neuromusculaire, Centre Universitaire des Saints-Pères, Université René Descartes, Paris, France.
authors.forename: Bruno
authors.initials: B
authors.lastname: Della Gaspera
authors.forename: Ines
authors.initials: I
authors.lastname: Sequeira
authors.forename: Frederic
authors.initials: F
authors.lastname: Charbonnier
authors.forename: Christel
authors.initials: C
authors.lastname: Becker
authors.forename: De-Li
authors.initials: DL
authors.lastname: Shi
authors.forename: Christophe
authors.initials: C
authors.lastname: Chanoine
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D004625:Embryo, Nonmammalian / Q000737:chemistry / Q000196:embryology / Q000378:metabolism; D047108:Embryonic Development; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006801:Humans; D008969:Molecular Sequence Data; D018006:Myogenic Regulatory Factors / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic / Q000235:genetics*; D014982:Xenopus laevis / Q000196:embryology* / Q000235:genetics / Q000378:metabolism*
chemical_list: D018076:DNA, Complementary; D018006:Myogenic Regulatory Factors; D012333:RNA, Messenger; C063403:myogenic factor 6