All members of the MHC multigene family respond to thyroid hormone in a highly tissue-specific manner

S Izumo, B Nadal-Ginard, V Mahdavi - Science, 1986 - science.org
S Izumo, B Nadal-Ginard, V Mahdavi
Science, 1986science.org
In mammals different isoforms of myosin heavy chain are encoded by the members of a
multigene family. The expression of each gene of this family is regulated in a tissue-and
developmental stage-specific manner as well as by hormonal and various pathological
stimuli. In this study the molecular basis of isoform switches induced in myosin heavy chain
by thyroid hormone was investigated. The expression of the myosin heavy chain gene family
was analyzed in seven different muscles of adult rats subjected to hypo-or hyperthyroidism …
In mammals different isoforms of myosin heavy chain are encoded by the members of a multigene family. The expression of each gene of this family is regulated in a tissue- and developmental stage-specific manner as well as by hormonal and various pathological stimuli. In this study the molecular basis of isoform switches induced in myosin heavy chain by thyroid hormone was investigated. The expression of the myosin heavy chain gene family was analyzed in seven different muscles of adult rats subjected to hypo- or hyperthyroidism with complementary DNA probes specific for six different myosin heavy chain genes. The results demonstrate that all six genes are responsive to thyroid hormone. More interestingly, the same myosin heavy chain gene can be regulated by thyroid hormone in highly different modes, even in opposite directions, depending on the tissue in which it is expressed. Furthermore, the skeletal embryonic and neonatal myosin heavy chain genes, so far considered specific to these two developmental stages, can be reinduced by hypothyroidism in specific adult muscles.
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