Angela Krämer

Research Focus

We study splicing proteins that recognise the 3’ splice site at the onset of spliceosome assembly. Our main focus is human splicing factor SF1, which interacts with U2AF65 and specifically recognises the intron branch site. Following the observation that SF1 is not a constitutive splicing factor, we have used in vivo cross-linking and immunoprecipitation (CLIP) and identified pre-mRNAs, whose alternative splicing is regulated by SF1.

We are currently testing how SF1 mediates alternative splice site choice of model pre-mRNAs in vivo and in vitro. Other projects are aimed at the identification of proteins that cooperate with SF1 in splice site selection and the analysis of expression and function of various SF1 isoforms.


  1. Tanackovic, G., and Krämer, A. (2005). Human splicing factor SF3a, but not SF1, is essential for pre-mRNA splicing in vivo. Molecular Biology of the Cell 16, 1366-1377.
  2. Kralovicova, J., Houngninou-Molango, S., Krämer, A., and Vorechovsky, I. (2004). Branch site haplotypes that control alternative splicing. Human Molecular Genetics 13, 3189-3202.
  3. Selenko, P., Gregorovic, G., Sprangers, R., Stier, G., Rhani, Z., Krämer, A., and Sattler, M. (2003). Structural basis for the molecular recognition between human splicing factors U2AF65 and SF1/mBBP. Molecular Cell 11, 965-976.
  4. Liu, Z., Luyten, I., Bottomley, M. J., Messias, A. C., Houngninou-Molango, S., Sprangers, R., Zanier, K., Krämer, A., and Sattler, M. (2001). Structural basis for recognition of the intron branch site RNA by splicing factor 1. Science 294, 1098-1102.
  5. Wang, X., Bruderer, S., Rafi, Z., Xue, J., Milburn, P. J., Krämer, A., and Robinson, P. J. (1999). Phosphorylation of splicing factor SF1 on Ser20 by cGMP-dependent protein kinase regulates spliceosome assembly. EMBO Journal 18, 4549-4559. 

Key lab techniques: in vitro and in vivo splicing, protein-protein interactions, protein-RNA interactions, RNA interference, CLIP technology.

Key lab reagents: SF1 antibodies and plasmids.

Lab contact: Angela Krämer:

Lab website: