Defect in cytokinesis of fission yeast induced by mutation in the WD40 repeat motif of a TFIID subunit.
BACKGROUND
TBP-associated factors contain a variety of structural motifs and their related in vivo significance has remained unclear. We have attempted to identify specific biological phenomena linked to a particular domain of a TAF by analysing domain-exchanged chimeric mutants between Schizosaccharomyces pombe (Sp) and Saccharomyces cerevisiae (Sc) counterparts.


RESULTS
Contrary to the case of TBP, Sp TAF containing the WD40 repeat cannot be exchanged for its Sc counterpart, despite their highly conserved primary structures. This 'species-specific' function locates in the N-terminal region. The C-terminal region, largely consisting of the WD40 repeat, is exchangeable for the corresponding region of its Sc counterpart. Growth of the strain harbouring this C-terminal chimeric mutant is temperature-sensitive. The chimeric gene product did not disappear at a restrictive temperature, a finding which strongly suggests that the growth defect is caused by an aberration in the interactions through the WD40 repeat structural motif. With temperature elevation, the chimeric mutants underwent drastic morphological changes due to a defect in cytokinesis.


CONCLUSIONS
The WD40 repeat of TAF is primarily involved in reactions which might regulate cytokinesis in Sp.
Yamamoto
T
T
Department of Cellular Biology, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Japan.
Horikoshi
M
M
D002455:Cell Division / Q000235:genetics; D004268:DNA-Binding Proteins / Q000737:chemistry / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics; D015870:Gene Expression; D005816:Genetic Complementation Test; D009154:Mutation; D011993:Recombinant Fusion Proteins / Q000235:genetics; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics* / Q000254:growth & development; D013045:Species Specificity; D013696:Temperature; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII / Q000737:chemistry / Q000235:genetics*
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; D011993:Recombinant Fusion Proteins; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII