diff --git a/eliot/_output.py b/eliot/_output.py
index ddba4b1..6c08e72 100644
--- a/eliot/_output.py
+++ b/eliot/_output.py
@@ -7,9 +7,10 @@
 import sys
 import json as pyjson
 
-from characteristic import attributes
 from six import text_type as unicode, PY3
 
+from pyrsistent import PClass, field
+
 from . import _bytesjson as slow_json
 if PY3:
     fast_json = slow_json
@@ -340,8 +341,7 @@ def reset(self):
 
 
 
-@attributes(["file"])
-class FileDestination(object):
+class FileDestination(PClass):
     """
     Callable that writes JSON messages to a file.
 
@@ -355,23 +355,27 @@ class FileDestination(object):
 
     @ivar _linebreak: C{"\n"} as either bytes or unicode.
     """
+    file = field(mandatory=True)
+    _dumps = field(mandatory=True)
+    _linebreak = field(mandatory=True)
 
-    def __init__(self):
+    def __new__(cls, file):
         unicodeFile = False
         if PY3:
             try:
-                self.file.write(b"")
+                file.write(b"")
             except TypeError:
                 unicodeFile = True
 
         if unicodeFile:
             # On Python 3 native json module outputs unicode:
-            self._dumps = pyjson.dumps
-            self._linebreak = u"\n"
+            _dumps = pyjson.dumps
+            _linebreak = u"\n"
         else:
-            self._dumps = fast_json.dumps
-            self._linebreak = b"\n"
-
+            _dumps = fast_json.dumps
+            _linebreak = b"\n"
+        return PClass.__new__(
+            cls, file=file, _dumps=_dumps, _linebreak=_linebreak)
 
     def __call__(self, message):
         """
diff --git a/eliot/_validation.py b/eliot/_validation.py
index fd7af2a..07060fe 100644
--- a/eliot/_validation.py
+++ b/eliot/_validation.py
@@ -7,11 +7,11 @@
 
 from __future__ import unicode_literals
 
-from collections import namedtuple
-
 import six
 unicode = six.text_type
 
+from pyrsistent import PClass, field as pyrsistent_field
+
 from ._message import (
     Message,
     REASON_FIELD,
@@ -333,12 +333,13 @@ def __call__(self, **fields):
 
 
 
-class _ActionSerializers(namedtuple("_ActionSerializers",
-                                    ["start", "success", "failure"])):
+class _ActionSerializers(PClass):
     """
     Serializers for the three action messages: start, success and failure.
     """
-
+    start = pyrsistent_field(mandatory=True)
+    success = pyrsistent_field(mandatory=True)
+    failure = pyrsistent_field(mandatory=True)
 
 
 class ActionType(object):
@@ -404,12 +405,12 @@ def makeActionStatusField(value):
             EXCEPTION]
 
         self._serializers = _ActionSerializers(
-            _MessageSerializer(startFields),
-            _MessageSerializer(successFields),
+            start=_MessageSerializer(startFields),
+            success=_MessageSerializer(successFields),
             # Failed action messages can have extra fields from exception
             # extraction:
-            _MessageSerializer(failureFields,
-                               allow_additional_fields=True))
+            failure=_MessageSerializer(failureFields,
+                                       allow_additional_fields=True))
 
 
     def __call__(self, logger=None, **fields):
diff --git a/eliot/testing.py b/eliot/testing.py
index 1321043..09831b7 100644
--- a/eliot/testing.py
+++ b/eliot/testing.py
@@ -5,9 +5,10 @@
 from __future__ import unicode_literals
 
 from unittest import SkipTest
-from collections import namedtuple
 from functools import wraps
 
+from pyrsistent import PClass, field
+
 from ._action import (
     ACTION_STATUS_FIELD,
     ACTION_TYPE_FIELD,
@@ -56,8 +57,7 @@ def assertContainsFields(test, message, fields):
 
 
 
-class LoggedAction(namedtuple(
-        "LoggedAction", "startMessage endMessage children")):
+class LoggedAction(PClass):
     """
     An action whose start and finish messages have been logged.
 
@@ -70,6 +70,14 @@ class LoggedAction(namedtuple(
     @ivar children: A C{list} of direct child L{LoggedMessage} and
         L{LoggedAction} instances.
     """
+    startMessage = field(mandatory=True)
+    endMessage = field(mandatory=True)
+    children = field(mandatory=True)
+
+    def __new__(cls, startMessage, endMessage, children):
+        return PClass.__new__(cls, startMessage=startMessage,
+                              endMessage=endMessage, children=children)
+
     @property
     def start_message(self):
         return self.startMessage
@@ -193,12 +201,17 @@ def succeeded(self):
 
 
 
-class LoggedMessage(namedtuple("LoggedMessage", "message")):
+class LoggedMessage(PClass):
     """
     A message that has been logged.
 
     @ivar message: A C{dict}, the message contents.
     """
+    message = field(mandatory=True)
+
+    def __new__(cls, message):
+        return PClass.__new__(cls, message=message)
+
     @classmethod
     def ofType(klass, messages, messageType):
         """
diff --git a/eliot/tests/test_action.py b/eliot/tests/test_action.py
index 2223a14..4586ada 100644
--- a/eliot/tests/test_action.py
+++ b/eliot/tests/test_action.py
@@ -597,7 +597,9 @@ def test_startTaskSerializers(self):
         resulting L{Action}.
         """
         logger = MemoryLogger()
-        serializers = _ActionSerializers(None, None, None)
+        serializers = _ActionSerializers(start=None,
+                                         success=None,
+                                         failure=None)
         action = startTask(logger, "sys:do", serializers)
         self.assertIs(action._serializers, serializers)
 
@@ -608,7 +610,9 @@ def test_startActionSerializers(self):
         resulting L{Action}.
         """
         logger = MemoryLogger()
-        serializers = _ActionSerializers(None, None, None)
+        serializers = _ActionSerializers(start=None,
+                                         success=None,
+                                         failure=None)
         action = startAction(logger, "sys:do", serializers)
         self.assertIs(action._serializers, serializers)
 
diff --git a/setup.py b/setup.py
index 781258b..5532167 100644
--- a/setup.py
+++ b/setup.py
@@ -41,8 +41,6 @@ def read(path):
         "six",
         # Internal code documentation:
         "zope.interface",
-        # Struct-like objects:
-        "characteristic",
         # Persistent objects for Python:
         "pyrsistent >= 0.11.8",  # version with multi-type pvector/pmap_field
     ],