Cloning and characterization of two putative seven-transmembrane receptor genes from cotton

Using rapid amplification of cDNA ends (RACE)-PCR, two full-length cDNAs encoding putative seven-transmembrane receptors (designated Gh7TMpR1 and Gh7TMpR2) were cloned from cotton plants. Southern blot and an ApaL1 restriction site polymorphism analyses revealed that Gh7TMpR1 was derived from the ancestral A diploid genome while Gh7TMpR2 was from the D subgenome. Northern blot hybridization indicated that both Gh7TMpR1 and Gh7TMpR2 were expressed preferentially in the elongation phase of fiber development. Majority of the Gh7TMpR1 proteins were located within the membrane structure and displayed a punctuate pattern of distribution. Overexpression of Gh7TMpR1 in fission yeast disrupted the polar growth and caused the formation of round-up cells. These results suggest that GhT7MpR1 may play a critical role in cotton fiber development, perhaps as a signaling receptor that is involved in controlling fiber elongation.