Mechanisms of Ageing and Development
100 (1998) 197–208
Cell proliferation and ku protein expression in
ageing humans
Daniela Frasca
a,
*, Paola Barattini
a
, Cristina Goso
a
,
Sabina Pucci
a
, Giovanni Rizzo
a
, Carlo Bartoloni
b
,
Mario Costanzo
b
, Andrea Errani
b
, Luisa Guidi
b
,
Leonardo Antico
b
, Augusto Tricerri
b
, Gino Doria
a
a
Laboratory of Immunology, ENEA CR Casaccia, Via Anguillarese 301, 00060 S. Maria di Galeria,
Rome, Italy
b
Institute of Internal Medicine, Catholic Uniersity of Rome, Rome, Italy
Received 19 June 1997; accepted 20 September 1997
Abstract
Previous studies on DNA repair in ageing have demonstrated increased frequencies of
single and double strand breaks in lymphocytes from elderly subjects and, as a consequence,
decreased efficiency in DNA replication. We have investigated the relationship between cell
proliferation and the nuclear expression of ku protein in a human population of 43 subjects
of different ages. Ku is an heterodimeric protein composed of two subunits of 70 and 80
kDa, which is involved in the early steps of DNA damage recognition. In the present study,
PBL from subjects of different ages were PHA-activated to evaluate the stimulation index
and the production of Th1- and Th2-type cytokines. Moreover, nuclear extracts were
obtained from activated lymphocytes to evaluate by a gel retardation assay the presence and
the functional activity of the heterodimer ku 70/80. Our results indicate that ageing affects
the mitotic responsiveness and cytokine production to a significant extent, but only mar-
ginally the expression of ku 70/80. These findings suggest that the age-related impairment in
DNA repair mechanisms are only in part related to the reduced expression of ku protein able
to recognize DNA damage. © 1998 Published by Elsevier Science Ireland Ltd.
Keywords: Ageing; Cell proliferation; Ku protein
* Corresponding author. Tel.: +39 6 30484031; fax: +39 6 30483644; e-mail: frasca@casaccia.enea.it
0047-6374/98/$19.00 © 1998 Published by Elsevier Science Ireland Ltd. All rights reserved.
PII S0047-6374(97)00137-1