ldap issue

hi,
I configured ldap:
dn: uid=testuser,ou=users,dc=example,dc=com
objectClass: posixAccount
objectClass: shadowAccount
objectClass: inetOrgPerson
cn: First Name
sn: Last Name
uid: testuser
uidNumber: 5000
gidNumber: 5000
homeDirectory: /home/testuser
loginShell: /bin/sh
gecos: Comments
userPassword:: e1NIQX00VVoycnNBZ2FkVkVhamJDdUZqTTZaUit6a009IA==

# Group1, users, example.com
dn: cn=Group1,ou=users,dc=example,dc=com
cn: Group1
objectClass: top
objectClass: posixGroup
gidNumber: 5001
memberUid: testuser

then

id testuser
uid=5000(testuser) gid=5000 groups=5000

why Group1 is missing?

getent group Group1
Group1:*:5001:

tnx