passages.id: split_8_test_139_passage
passages.type: progene_text
passages.text: We show that R-FABP mRNA and the AP-2 factors are expressed in mutually exclusive patterns in the differentiating retina : whereas AP-2alpha and AP-2beta are selectively expressed either in amacrine , or in amacrine and horizontal cells , respectively , R-FABP mRNAis found in Muller glial cells and/or bipolar cells .