#                         1         2         3
#                123456789012345678901234567890
my $str_type1 = "ccaatTTTGACACACACAGAAgggca"; # no dash
my $str_type2 = "--aatTTTGACACACACAGAAgggca"; # with dash

for ( $str_type1, $str_type2 )
{
    if ( m{^(-*)[^A-Z]*([A-Z]*)} )
    {
        my ( $s, $e ) = ( $-[2] + 1, $+[2] );
        $_ -= length $1 for $s, $e;
        print "$_\n";
        print "From = $s to $e\n\n";
    }
}
#output:
ccaatTTTGACACACACAGAAgggca
From = 6 to 21

--aatTTTGACACACACAGAAgggca
From = 4 to 19