Abstract
The small nuclear RNA-activating protein complex SNAPc is required for transcription of small nuclear RNA genes and binds to a proximal sequence element in their promoters. SNAPc contains five types of subunits stably associated with each other. Here we show that one of these polypeptides, SNAP45, also known as PTF δ, localizes to centrosomes during parts of mitosis, as well as to the spindle midzone during anaphase and the mid-body during telophase. Consistent with localization to these mitotic structures, both down- and up-regulation of SNAP45 lead to a G2/M arrest with cells displaying abnormal mitotic structures. In contrast, down-regulation of SNAP190, another SNAPc subunit, leads to an accumulation of cells with a G0/G1 DNA content. These results are consistent with the proposal that SNAP45 plays two roles in the cell, one as a subunit of the transcription factor SNAPc and another as a factor required for proper mitotic progression.
Highlights
Many biological processes are combinatorial, using the principle of mixing limited numbers of individual elements to give rise to nearly unlimited numbers of combinations with different functional attributes
A classical example occurs in promoters, where different arrangements of sequence elements result in the recruitment of different combinations of transcription factors that can provide the complex regulation needed for processes such as differentiation and development. Another example is in the repeated use of various polypeptides in different protein complexes. In some cases, such as the TBP-associated factors (TAFs) present in both the transcription factor IID (TFIID) and Spt-Ada-Gen5 acetyltransferase (SAGA) complexes [1, 2], the resulting complexes are involved in the same general process, in this example transcription
The snRNA-activating protein complex SNAPc is a multisubunit complex containing five types of subunits, SNAP190, SNAP50, SNAP45, SNAP43, and SNAP19, that is required for RNA polymerase II and III transcription of the human snRNA2 genes
Summary
Many biological processes are combinatorial, using the principle of mixing limited numbers of individual elements to give rise to nearly unlimited numbers of combinations with different functional attributes. As subunits gave staining patterns similar to those observed with shown in supplemental Fig. 1A, methanol fixation resulted in a the anti-SNAP45 antibody (data not shown), consistent with loss of much of the DNA-overlapping SNAP45 signal in late the idea that SNAP45 may play a role during mitosis that is
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
