Representative fluorescence micrographs of Arabidopsis mesophyll protoplasts.

<p>Purified protoplasts were transformed with (A) full length ATHB17:GFP or (B) a variant lacking the first 73 amino acids (ATHB17Δ73:GFP). The full length ATHB17:GFP fusion protein localizes to the nucleus and cytosol (A) in Arabidopsis protoplasts and ATHB17Δ73:GFP is localized exclusively in the nucleus when the unique N- terminus is removed (B). Two regions with a cluster of basic (K and R) residues were identified as putative nuclear localization signals. The arginine residues were mutated to alanines in these regions in the Δ73 variant to disrupt translocation. (C) R138A and R142A mutations in ATHB17 Δ73 disrupted nuclear retention while (D) R187A, R188A and R190A mutations did not alter the nuclear localization of the Δ73 variant.