diff --git a/google/cloud/spanner_v1/services/spanner/client.py b/google/cloud/spanner_v1/services/spanner/client.py
index e853b2dfd5..d69c427314 100644
--- a/google/cloud/spanner_v1/services/spanner/client.py
+++ b/google/cloud/spanner_v1/services/spanner/client.py
@@ -370,16 +370,17 @@ def get_mtls_endpoint_and_cert_source(
         )
         if client_options is None:
             client_options = client_options_lib.ClientOptions()
-        use_client_cert = os.getenv("GOOGLE_API_USE_CLIENT_CERTIFICATE", "false")
-        use_mtls_endpoint = os.getenv("GOOGLE_API_USE_MTLS_ENDPOINT", "auto")
-        if use_client_cert not in ("true", "false"):
-            raise ValueError(
-                "Environment variable `GOOGLE_API_USE_CLIENT_CERTIFICATE` must be either `true` or `false`"
-            )
-        if use_mtls_endpoint not in ("auto", "never", "always"):
-            raise MutualTLSChannelError(
-                "Environment variable `GOOGLE_API_USE_MTLS_ENDPOINT` must be `never`, `auto` or `always`"
-            )
+
+        (
+            use_client_cert,
+            use_mtls_endpoint,
+            universe_domain_env,
+        ) = SpannerClient._read_environment_variables()
+
+        universe_domain_opt = getattr(client_options, "universe_domain", None)
+        universe_domain = SpannerClient._get_universe_domain(
+            universe_domain_opt, universe_domain_env
+        )
 
         # Figure out the client cert source to use.
         client_cert_source = None
@@ -397,7 +398,9 @@ def get_mtls_endpoint_and_cert_source(
         ):
             api_endpoint = cls.DEFAULT_MTLS_ENDPOINT
         else:
-            api_endpoint = cls.DEFAULT_ENDPOINT
+            api_endpoint = SpannerClient._DEFAULT_ENDPOINT_TEMPLATE.format(
+                UNIVERSE_DOMAIN=universe_domain
+            )
 
         return api_endpoint, client_cert_source
 
diff --git a/google/cloud/spanner_v1/testing/database_test.py b/google/cloud/spanner_v1/testing/database_test.py
index 5af89fea42..800cabaad0 100644
--- a/google/cloud/spanner_v1/testing/database_test.py
+++ b/google/cloud/spanner_v1/testing/database_test.py
@@ -110,7 +110,7 @@ def _create_spanner_client_for_tests(self, client_options, credentials):
             default_host=SpannerTransport.DEFAULT_HOST,
         )
         channel = grpc.intercept_channel(channel, *self._interceptors)
-        transport = SpannerGrpcTransport(channel=channel)
+        transport = SpannerGrpcTransport(channel=channel, host=api_endpoint)
         return SpannerClient(
             client_options=client_options,
             transport=transport,
diff --git a/testing/constraints-3.12.txt b/testing/constraints-3.12.txt
index ad3f0fa58e..e8a39cf7b5 100644
--- a/testing/constraints-3.12.txt
+++ b/testing/constraints-3.12.txt
@@ -5,3 +5,8 @@ google-api-core
 proto-plus
 protobuf
 grpc-google-iam-v1
+grpc-interceptor
+google-cloud-core
+google-cloud-testutils
+mock
+sqlparse
\ No newline at end of file
diff --git a/tests/system/_helpers.py b/tests/system/_helpers.py
index 1fc897b39c..97bb8f8b96 100644
--- a/tests/system/_helpers.py
+++ b/tests/system/_helpers.py
@@ -27,7 +27,7 @@
 CREATE_INSTANCE = os.getenv(CREATE_INSTANCE_ENVVAR) is not None
 
 INSTANCE_ID_ENVVAR = "GOOGLE_CLOUD_TESTS_SPANNER_INSTANCE"
-INSTANCE_ID_DEFAULT = "google-cloud-python-systest"
+INSTANCE_ID_DEFAULT = "test-instance-1"
 INSTANCE_ID = os.environ.get(INSTANCE_ID_ENVVAR, INSTANCE_ID_DEFAULT)
 
 API_ENDPOINT_ENVVAR = "GOOGLE_CLOUD_TESTS_SPANNER_HOST"
diff --git a/tests/system/conftest.py b/tests/system/conftest.py
index bc94d065b2..fe2930cb4f 100644
--- a/tests/system/conftest.py
+++ b/tests/system/conftest.py
@@ -16,6 +16,7 @@
 import time
 
 import pytest
+from google.api_core.client_options import ClientOptions
 
 from google.cloud import spanner_v1
 from google.cloud.spanner_admin_database_v1 import DatabaseDialect
@@ -105,9 +106,12 @@ def spanner_client():
             credentials=credentials,
         )
     else:
-        client_options = {"api_endpoint": _helpers.API_ENDPOINT}
         return spanner_v1.Client(
-            client_options=client_options
+            project="tpczero-system:bootstrap-libraries",
+            client_options=ClientOptions(
+                api_endpoint=_helpers.API_ENDPOINT,
+                universe_domain="apis-tpczero.goog",
+            )
         )  # use google.auth.default credentials
 
 
diff --git a/tests/system/test_database_api.py b/tests/system/test_database_api.py
index 57ce49c8a2..ae5856b064 100644
--- a/tests/system/test_database_api.py
+++ b/tests/system/test_database_api.py
@@ -37,7 +37,7 @@
     "include_replicas": {
         "replica_selections": [
             {
-                "location": "us-west1",
+                "location": "u-us-prp1",
                 "type_": DirectedReadOptions.ReplicaSelection.Type.READ_ONLY,
             },
         ],
@@ -281,7 +281,7 @@ def test_iam_policy(
 
     new_binding = policy_pb2.Binding(
         role="roles/spanner.fineGrainedAccessUser",
-        members=["user:asthamohta@google.com"],
+        members=["user:sasubramanian@google.com"],
         condition=expr_pb2.Expr(
             title="condition title",
             expression='resource.name.endsWith("/databaseRoles/parent")',