ARTICLES
Cell Research (1997)7:179-193
© 1997 SIBS, CAS All rights reserved 1001-0602/97
Characterization of the Xenopus homolog of an immediate early
gene associated with cell activation: sequence analysis and regulation
of its expression by thyroid hormone during amphibian metamorphosis.
Liang VC, Sedgwick T, Shi YB.
Laboratory of Molecular Embryology NICHD/NIH, Bethesda, MD 20892-5431,
USA.
The complex transformation of a tadpole to a frog during amphibian development
is under the control of thyroid hormone (T3). T3 is known to regulate gene
transcription through its nuclear receptors. We have previously isolated
many genes which are up-regulated by T3 in the intestine of Xenopus laevis
tadpoles. We have now cloned a full-length cDNA for one such gene (IU12).
Sequence analysis shows that the IU12 cDNA encodes a plasma membrane protein
with 12 transmembrane domains and homologous to a mammalian gene associated
with cell activation and organ development. Similarly, we have found that
IU12 is activated during intestinal remodeling when both cell death and
proliferation take place. Furthermore, IU12 is an early T3-response gene
and its expression in the intestine during T3-induced metamorphosis mimics
that during normal development. These results argue for a role of IU12 in
the signal transduction pathways leading to intestinal metamorphosis.
Keywords : Thyroid
hormone, Xenopus laevis, cell proliferation, organogenesis, transcription
factor. |
