Identification of differentially expressed genes in thyrotropin stimulated dog thyroid cells by the cDNA-AFLP technique.

In dog thyrocytes in primary culture, thyrotropin (TSH), through cAMP, positively controls proliferation and differentiation. As until now, the key events and the genes involved in the action of TSH remain largely uncharacterized, our goal was to identify new differentially expressed genes in TSH-induced thyroid proliferation. Using cDNA-AFLP, we visualized 105 different transcripts showing significant differential expression during the stimulation of dog thyrocytes with TSH for different times, in the presence of insulin. Northern blot and RT-PCR analyses confirmed the pattern expression of 5 clones encoding known proteins: thrombospondine 1, TNFr1, RhoE, RalB, and annexin A2. These regulations provide molecular counterparts of in vivo physiological effects of TSH: angiogenesis (decreased thrombospondin 1), decreased apoptosis (decreased TNFR1) and actin filament disruption, macropinocytosis and thyroid hormone secretion (decreased RhoE).