Small example
syms s
Numerator=[1];
Denominator=[1 0 1];
sys=tf(Numerator,Denominator)
ex=evalc('sys')
[a b] = strread(ex, '%s %s', 'delimiter',char(10));
num=char(a(2));
den=char(a(3));
Now you have the numerator and denominator that can be used in the String of some GUI object like the edit or text