Fig. 1. Construction and expression of p35 in the rat brain. (A ) Schematic drawing of the Thy1 expression cassette with insertion of p35 complementary DNA using an Xho  I restriction site. (B ) Northern blot analysis of Thy1EμP35 transgenic rats. Lanes 1–3  contain 3 μg per lane polyA+ brain RNA from nontransgenic rats (lane 1 ), line L25 rats (lane 2 ), and line L24 rats (lane 3 ). Arrow  indicates p35 messenger RNA. Bars  show the ribosomal position of 28S and 18S RNA. Lanes 4–10  contain 10 μg per lane total RNA from rat brain (lanes 4–6 ) and thymus (lanes 7–10 ) of transgenic animals (lanes 4, 5, 8, 9 , and 10 ) and nontransgenic littermates (lanes 6  and 7 ). (C ) Western blot analysis of brain extracts from transgenic rats. Lane 1 = transgenic rat line L24;lane 2 = nontransgenic rat brain extract. Asterisks  show position of p35 protein in gel. (D ) In situ  hybridization analysis of p35. The image of the transgenic Thy1EμP35 rat brain is shown at the hippocampal level; no background signal was detected in brains of the control group (data not shown).