dat<- data.frame(
  Gene_Name= LETTERS[1:15], 
  Value1 = sample(-8:20,15,replace=TRUE),
  Value2 =sample(-6:10,15,replace=TRUE)
)
 
library(rCharts)
r1<- nPlot(Value1~Value2,data=dat, type="scatterChart")
r1$chart(tooltipContent = "#! function(key, x, y, e){
  return '<b>Gene Name</b>: ' + e.point.Gene_Name
} !#")
r1