The TCL1 gene, which is located on chromosome 14, plays a major role in hum
an hematopoietic malignancies and encodes a 14-kDa protein whose function h
as not been determined. This gene is expressed in pre-B cells, in immature
thymocytes, and, at low levels, in activated T cells but not in peripheral
mature B cells and in normal cells. The Tell protein is similar in its prim
ary structure to a protein encoded by the mature T-cell proliferation gene
(MTCP1). The MTCP1 gene is located on the X chromosome and has been shown t
o be involved in rare chromosomal translocations in T-cell proliferative di
seases. The murine TCL1 gene resides on mouse chromosome 12 and is homologo
us to the human TCL1 and MTCP1 genes. Murine Tcl1 protein has 116 amino aci
d residues and shares 50% sequence identity with human Tcl1, while the huma
n and mouse Mtcp1 are nearly identical, with conservative differences in on
ly six residues. The TCL1 and MTCP1 genes appear to be members of a family
of genes involved in lymphoid proliferation and T-cell malignancies. Our la
boratory has undertaken the study of the Tcl1 and Mtcp1 proteins to determi
ne the structure and the function of these related proteins. In the present
report, we have produced, using a bacterial expression system, the purifie
d murine Tcl1 protein and a mutant form of murine Tcl1 protein containing a
cysteine to alanine mutation at amino acid position 85. The recombinant pr
oteins were purified by chromatography on a Ni-NTA resin followed by revers
e-phase FPLC using a buffer system at pH 7.9 and a polymer-based reverse-ph
ase column. The murine Tell recombinant protein displays limited solubility
and forms disulfide-linked dimers and oligomers, while the mutant murine T
ell C86A protein has increased solubility and does not form higher order ol
igomers, The purified recombinant murine proteins were characterized by N-t
erminal sequence analysis, mass spectrometry, and circular dichroism spectr
oscopy. Initial results indicate that the mutant murine Tell C86A protein i
s suitable for both NMR and X-ray crystallographic methods of structure det
ermination. (C) 2000 Academic Press.