Chamando função de outro script

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SCRIPT 1:
using UnityEngine;
using System.Collections;
using System.Text.RegularExpressions;

public class PlayerMenu : MonoBehaviour {


    public GUISkin skin2;

    public bool teste = true;

    private LevelMode fase1_levelMode;


    void Start ()
    {
        fase1_levelMode = GetComponent <LevelMode> ();
    }


    void OnGUI()
    {
        GUI.skin = skin2;
        if (GUI.Button (new Rect (200, 400, 200, 50), "Teste"))
        {
            fase1_levelMode.callGameMode1 ();
            teste = false;
        }
    }
}

// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ SCRIPT 2:

using UnityEngine;
using System.Collections;
using System.Text.RegularExpressions;

public class LevelMode : MonoBehaviour {

    PlayerMenu pm;

    public void callGameMode1 ()
    {
        print ("teste");
    }
}