Pear1 in zebrafish is a negative regulator of thrombocyte production. (A) Western blot for PEAR1 (PEAR1-EC Ab) in zebrafish, noninjected, injected with control MO, or PEAR1 ATG MO 3 days postfertilization (dpf); total Akt served as loading control. (B) Analysis of the number of GFP-positive cells in the tail at 2 dpf after PEAR1 MO injection vs control. (C) PEAR1 knockdown and thrombocyte production. Photography of CD41:eGFP fish at 3 dpf after injection with control or PEAR1 ATG MO with white light (top) and with fluorescent light (bottom). (D) Western blot of GFP expression and quantification at 3 dpf in whole fish after injection with control or PEAR1 ATG or PEAR1 splice MO, with Akt as loading control. (E) mRNA expression of Gata-1 and Scl, general markers for erythrocytes and HSCs, by qRT-PCR after treatment with control or PEAR1 MOs. (F) PEAR1 knockdown in erythrocyte production: photography of GATA1:dsred fish at 3 dpf after injection with control or PEAR1 ATG MO with fluorescent light (top); o-dianisidine staining of CD41:eGFP whole fish at 48 hpf and after injection with control or PEAR1 ATG MO (lower). (G) Analysis of area density for stained red blood cells after injection with control or PEAR1 ATG MO.