Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
???displayArticle.abstract???
A cDNA clone for a Xenopus laevis skeletal muscle beta-tropomyosin (beta-TMad) isoform was isolated from an adult skeletal muscle cDNA library. Sequence analysis revealed that this clone corresponded to a second beta-tropomyosin mRNA distinct from the one that was previously characterized (beta-TMemb). The two skeletal beta-TM mRNAs originate from distinct genes and are differentially expressed during development. Beta-TMemb mRNA is expressed only in the somites of the early embryo while beta-TMad mRNA is expressed in pre-metamorphic tadpoles and adult skeletal muscles. We have isolated the promoter region of the beta-TMemb gene and shown that a DNA construct containing 2.9 kb of promoter region is properly expressed after injection in the embryo.
Fig. 2. Expression of b-TMemb and b-TMad transcripts in embryos and
adult tissues. (A) The distribution of b-TMemb and b-TMad transcripts
was analyzed by RT-PCR. RNA was from eggs (Eg), different staged
embryos (22-48), body (B) and tail (T) muscles of pre-metamorphic stage 57
tadpoles, adult skeletal muscle (Sk) and stomach (St). tRNA (-) was used as
control. (B)Whole-mount in situ analysis of b-TMemb transcripts. Embryos
were stained at stage 25, 28 and 35. (C) In situ hybridization on transverse
sections of a stage 25 (upper) and stage 35 (lower) embryo.
tpm2 (tropomyosin 2 (beta)) gene expression in Xenopus laevis embryos, NF stage 35, as assayed by in situ hybridization. Lateral view: anteriorleft, dorsal up.
Fig. 3. Xenopus laevis b-TMemb gene 5' structure and transcriptional
activation of the promoter region in the embryo. (A) Schematic
representation of the 13 kb genomic clone. Exons are figured by black
boxes and 5'UTR by an open box. Major restriction enzymes sites are
BamHI (B), EcoRI (E), HindIII (H) and KpnI (K). (B) RNase mapping of the
transcription start site. Total RNA from eggs (Eg), skeletal muscle (Sk),
stomach (St), oviduct (Ov), embryo (Emb) or tRNA (-) were analyzed as
described in Experimental Procedures. Similar size major products of 69
and 74-77 nt are detected in embryo and smooth muscle tissues. (C) CAT
activity detection in Xenopus oocytes and embryos injected with the 2.9 kb
b-TM/CAT plasmid construction. Embryos are from stage 12 (12), 18 (18),
24 (24) 28 (28), and ventral (V) or dorsal (D) part of a stage 28 embryo. The
promoterless plasmid PBCOCAT was used as control (C). The migration of
the acetylated forms of chloramphenicol (CM) is indicated by arrows.
