** Description

This document contains one of two graphs provided for 
the 2003 Graph Drawing Contest.

It consists of a biological network representing the transcriptional
regulation of Escherichia coli, i.e. nodes represent operons and
transcription factors, and (directed) edges represent interactions.
Note that there are loops (autoregulation).

There is a string-valued node attribute (operon name) 
and an integer edge attribute (regulation type).

Particularly interesting about this network is the frequent
occurrence of small subgraphs, so-called motifs, described in 

Network motifs 
in the transcriptional regulation network of Escherichia coli
S S SHEN-ORR, R MILO, S MANGAN and U ALON, Nature Genetics 31(1):64-68

How can a visualization highlight such motifs using graph drawing methods?

Data courtesy of Uri Alon, The Weizmann Institute, Israel.

** DATA FORMAT

<int>no of nodes
<int>id_node1 <string>name
<int>id_node2 <string>name
<int>id_node3 <string>name
...

<int>no of edges
<int>id_source_node <int>id_target_node <int>type
...

where

name is Name of operon

type is 1: activator
	2: repressor
	3: dual