use strict;
use warnings;

my @strings = qw{
   ccaatTTTGACACACACAGAAgggca
   --aatTTTGACACACACAGAAgggca
   --aatTTTGACACACACAGAA
   ---aagctaagattca
   TTTGACACACACAGAAgggca
   ---TTTGACACACACAGAAgggca
   };

foreach my $string ( @strings )
{
    my ($sp, $ep) = ucRange($string);
    print
       qq{        String - $string\n},
       qq{Start position - $sp\n},
       qq{  End position - $ep\n\n};
}

sub ucRange
{
    local our $str = shift;
    $str =~ s{\A-*}{_};

    local our $startPos = 0;
    $str =~ m{(?<=[a-z_])(?=[A-Z])(?{$startPos = pos $str})};

    local our $endPos = 0;
    $str =~ m{(?<=[A-Z])(?=[A-Z](?:[a-z]|\z))(?{$endPos = pos $str})};

    return ($startPos, $endPos);
}