A great variety of vertebrate cells contain detectable amounts of lectins,
able to stimulate the initiation of cellular DNA synthesis. One of them, sa
rcolectin (SCL) can block interferon (IFN) action, by inhibiting the synthe
sis and the expression of the IFN dependent secondary proteins. As a result
, the IFN-induced antiviral state is abolished in the cells, which likely f
acilitates their replication. We identified a major 65 kDa and a minor 55 k
Da protein, which could carry these cellular functions. Their purification,
especially that of the 65 kDa, was difficult, because of the proximity of
albumin. We devised therefore a two-step primary separation, followed by a
four-step final purification, which are reported here. The purification was
controlled by high pressure liquid chromatography (HPLC), SDS-PAGE electro
phoresis and identified by Western blots. We found that only the minor 55 k
Da protein can be considered as being sarcolectin, while the major 65 kDa b
and results from the binding of some SCL molecules to albumin. The major bi
ological functions, namely, stimulation of DNA synthesis and cell agglutina
tion were preserved to the end of the last purification step. This work is
requisite for establishing the molecular structure of SCL by recombinant DN
A technology. (C) 1999 Societe francaise de biochimie et biologie moleculai
re / Editions scientifiques et medicales Elsevier SAS.