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Ciliary neurotrophic factor (CNTF), interleukin-6 (IL-6), leukemia inhibitory factor (LIF), and oncostatin M (OSM) share functional properties, a predicted common helical framework, and partially identical receptor components. CNTF is a survival promoting factor for various types of neurons in vitro and in vivo. In the present study, structural features essential for the biological function of human CNTF were investigated. Several recombinant CNTF variants were constructed by PCR and expressed in E. coli. Their survival promoting activities were determined using cultures of embryonic chick and newborn rat dorsal root ganglion cells. Deletion of 14 N-terminal and 18 C-terminal amino acids significantly increased bioactivity compared to wild-type (wt) CNTF. Further truncation of the CNTF molecule at the N- or C-terminus resulted in a significant reduction or complete loss of activity. Substitution of two amino acids (Lys154Glu and Trp157Pro) abolished the survival promoting effect. Recently described analogous substitutions in IL-6 had resulted in a partial IL-6 receptor antagonist. However, the double substitution variant had no significant inhibitory effect on wtCNTF activity in assays with both wt and mutant factor. The CNTF variants constructed had almost identical effects on both chick and rat neurons indicating a close similarity of the avian and the mammalian CNTF receptor complex. The present results also demonstrate that a core segment of the CNTF molecule is indispensable for biological function. Analogous segments important for activity have already been identified in the related molecules IL-6, LIF, and OSM. Thus, our data confirm the close structural relationship of CNTF to these "neuropoietic" cytokines. In addition, they demonstrate that site-directed mutagenesis of recombinant human CNTF can yield molecules which show increased survival promoting activity on mammalian neurons.
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
October 1996,
Gene,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
July 2003,
Biochemistry,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
May 1995,
Journal of lipid research,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
January 2002,
Biochimica et biophysica acta,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
December 1992,
Biochemistry,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
December 1990,
The Journal of biological chemistry,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
September 2013,
Biochimie,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
February 1994,
Biochimica et biophysica acta,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
November 2002,
Insect biochemistry and molecular biology,
M Thier, and
R Simon, and
A Krüttgen, and
S Rose-John, and
P C Heinrich, and
J M Schröder, and
J Weis
January 1993,
Methods in molecular biology (Clifton, N.J.),
