Mammalian Emx2. a homeobox tra nscripti on factor‘ is continuoll s ly expressecl in aclll lt neural s tem cell s of the b.ippo campal c1enclate gyrus (HDG) a f'ter blrth 1'0 c1ate‘ roles 01' Emx2 a ncl its llnderlying rnecha ni s rn in r eg비 atin g acl lllt neuro - genesis from neural stem cell aft er bi rth is still obscure. 1'he present experiment is aimed to elucidate role 01' Emx2 in regulating adll lt neurogenesis from neural s tem cell of HDG using nestin-Emx2 transgenic mouse (N-E2 1'G) and heterozygous Emx2 KO mouse (1-l-E2 KO) . HDG g ranlllar cell layer where new born neurons proclllced from adult neural stem cell migrate. is thin with low cell c1ens ity in N-E2 1'G but tbick with high cell density in H-E2 KO, compared to wild type mice (\\끼') . Number of DCX , a new born nellron marker. -positive cells is less in N-E2 1'G but more in l-l-E2 KO. comparecl to W1'. Ki67 (whole cell cycle marker) 01' BrclU (S-phase marker) 一positive cells is less in N-E2 1'G bllt morc in l-l-E2 KO and BrdU-positive cells/ Ki 67ratio is higher in N-E2 1'G but lower in H-E2 KO. NeuN (a mature n e llro삐 marker) a ncl BrdU-dollble positive cells is lUore in N- E2 TG bllt GFAP (a glial cell marker) ancl BrdU- dollble positive cells is more in ]-]- E2 KO. compa recl to WT 4wks after BrclU is aclmin istratecl one ti me per c1ay for 5days‘ Migrating c1egree of BrdU-positive cells is lower in N-E2 TG but higher in ]-]-E2 KO 4wks after BrclU is administratecl one t ime per day for 5days. Active casepase 3-positive cells is more in ]-]DG 01' the N-E2 TG but no changes in ]-]-E2 KO. 4 wks after CAG- GFP- PRE vector was inj ected in hippocampus. GFP-positive new born n e urons from aclult neural stem cell have less c1endritic branches in N-E2 1'G but more c1endritic branches in H-E2 KO‘ comparecl to the WT From these results. Emx2 transcription factor inhibits adult neurogenesis f'rom nellral stem cell of HDG throllgh reducing neural stem cell proliferation. new born cell survival. ce ll migration. ancl matllrat ion

• Won Jae Kim(Department of Physology and 2nd stage of BK21, School of Dentistry, Chonnam. Natonal University)