Lac Operon Regulation

digraph lac {
  rankdir=LR;
  graph [bgcolor=transparent];
  node [shape=box, style="rounded,filled", fontname=Inter, fontsize=10];

  Lactose [fillcolor="#dcfce7"];
  Allolac [label="Allolactose"];
  LacI [label="LacI repressor", fillcolor="#fee2e2"];
  Op [label="Operator (O)", fillcolor="#fef3c7"];
  Pro [label="Promoter (P)", fillcolor="#fef3c7"];
  Z [label="lacZ"]; Y [label="lacY"]; A [label="lacA"];
  RNAP [label="RNA polymerase", fillcolor="#dbeafe"];
  cAMP [label="cAMP-CAP", fillcolor="#dbeafe"];

  Lactose -> Allolac;
  Allolac -> LacI [label="inhibits"];
  LacI -> Op [label="binds (off)"];
  cAMP -> Pro [label="enhances binding"];
  RNAP -> Pro;
  Pro -> Z; Z -> Y; Y -> A;
}