Tuohy moved to Ulster from English Premiership side Exeter Chiefs, penning a two-year contract ahead of the 2009/10 season.
Having come through a strong Academy system in the Premiership with Gloucester, the 25-year-old had Ireland Under-21 honours to his name before his arrival in Belfast and with his excellent lineout abilities and good turn of pace, he has become a regular in the Ulster team over the past season-and-a-half.
Youngsters Paddy McAllister and Nevin Spence are both products of the Phoenix Ulster Rugby Academy.
Prop McAllister ,who was awarded a development contract ahead of the start of the current season, made his Ulster senior debut when coming on as a replacement against the Ospreys in September.
The Ballynahinch player, who has has represented Ireland at Schools, Under-19 and Under-20 levels, has featured regularly in the Ulster matchday squad this season.
Centre Spence also joined the Ulster squad on a development contract last summer after featuring for the Ireland Under-20s in their RBS U-20 6 Nations title-winning campaign.
The former Northern Ireland Under-16 football international made his first Ulster start against Glasgow last April and has started six matches for Ulster so far this season, scoring a memorable try in Ulster's away win over Bath last month, and another against Benetton Treviso last Friday.