Hi Laura,

Using TinkerGraph I exported a graph to graphSON in the way shown above. I reloaded it as follows:

gremlin> graph = TinkerGraph.open();
==>tinkergraph[vertices:0 edges:0]
gremlin> g = graph.traversal()
==>graphtraversalsource[tinkergraph[vertices:0 edges:0], standard]
gremlin> g.io('data/metatest.json').read().iterate()
gremlin> g.V().elementMap()
==>[id:1,label:person,name:marko,age:29]
==>[id:2,label:person,name:vadas,age:27]
==>[id:3,label:software,name:lop,lang:java]
==>[id:4,label:person,name:josh,age:32]
==>[id:5,label:software,name:ripple,lang:java]
==>[id:6,label:person,name:peter,age:35]
==>[id:13,label:person,name:turing]
gremlin> g.V(1).properties('name').elementMap()
==>[id:0,key:name,value:marko,metatest:hi]
gremlin>

So, the metaproperty added s read from graphSON. Do you mean to say that you cannot do the same with JanusGraph? I did not check myself.

Best wishes,    Marc