Translin-associated factor X is post-transcriptionally regulated by its partner protein TB-RBP, and both are essential for normal cell proliferation.


Journal Article

To determine the functions of the DNA/RNA-binding protein TB-RBP in somatic cells, we examined cultured primary mouse embryonic fibroblasts (MEFs) derived from TB-RBP-deficient mice. The TB-RBP-deficient MEFs exhibit a reduced growth rate compared with MEFs from littermates. Reintroduction of TB-RBP remedies this defect. A partner protein of TB-RBP, Translin-associated factor X (TRAX), was absent in TB-RBP-deficient MEFs, despite normal TRAX mRNA levels. TRAX is dependent upon the presence of TB-RBP and is removed from null MEFs following ubiquitination. Re-introduction of TB-RBP, but not TB-RBP lacking an oligomerization domain, into null MEFs stabilized TRAX protein without changing TRAX mRNA levels. The coordinated expression of TB-RBP and TRAX is also seen in synchronized cells, where the amount of TRAX protein but not TRAX RNA closely parallels TB-RBP levels throughout the cell cycle. In transgenic mice overexpressing TRAX in testis, total TB-RBP and TRAX levels are constant with reductions of endogenous TRAX compensating for exogenous TRAX. Using RNA interference, reductions of either TB-RBP or TRAX (without affecting TB-RBP) slow cell growth rates. We conclude that TRAX is post-transcriptionally stabilized by TB-RBP and both proteins are needed for normal cell proliferation.

Full Text

Cited Authors

  • Yang, S; Cho, YS; Chennathukuzhi, VM; Underkoffler, LA; Loomes, K; Hecht, NB

Published Date

  • March 2004

Published In

Volume / Issue

  • 279 / 13

Start / End Page

  • 12605 - 12614

PubMed ID

  • 14711818

Pubmed Central ID

  • 14711818

Electronic International Standard Serial Number (EISSN)

  • 1083-351X

International Standard Serial Number (ISSN)

  • 0021-9258

Digital Object Identifier (DOI)

  • 10.1074/jbc.m313133200


  • eng