K. Nagata et al., CELLULAR-LOCALIZATION AND EXPRESSION OF TEMPLATE-ACTIVATING FACTOR-I IN DIFFERENT CELL-TYPES, Experimental cell research, 240(2), 1998, pp. 274-281
Template-activating factors I (TAF-I) alpha and beta have been identif
ied as chromatin remodeling factors from human HeLa cells. TAF-I beta
corresponds to the protein encoded by the set gene, which was found in
an acute undifferentiated leukemia as a fusion version with the can g
ene via chromosomal translocation. To determine the localization of TA
F-I, we raised both polyclonal and monoclonal antibodies against TAF-I
. The proteins that react to the antibodies are present not only in hu
man cells but also in mouse, frog, insect, and yeast cells. The mouse
TAF-I homologue is ubiquitous in a variety of tissue cells, including
liver, kidney, spleen, lung, heart, and brain. It is of interest that
the amounts of TAF-I alpha and beta vary among hemopoietic cells and s
ome specific cell types do not contain TAF-I beta. The level of the TA
F-I proteins does not change significantly during the cell cycle progr
ession in either HeLa cells synchronized with an excess concentration
of thymidine or NIH 3T3 cells released from the serum-depleted state.
TAF-I is predominantly located in nuclei, while TAF-I that is devoid o
f its acidic region, the region which is essential for the TAF-I activ
ity, shows both nuclear and cytoplasmic localization. The localization
of TAF-I in conjunction with the regulation of its activity is discus
sed. (C) 1998 Academic Press.