BOK (gene) - Splice Variants

Splice Variants

Due to alternative splicing, Bok mRNA gives rise to different Bok proteins: Figure 1 illustrates the different splice variants schematically. Full length Bok is named Bok-L.

The shorter version, Bok-S, lacks exon 3. This results in a fusion of the BH3 domain with the BH1 domain. The BH3 domain is involved in the interaction of Bok with Mcl-1 and other molecules. It is dispensable for the induction of apoptosis. Expression of Bok-S may be an immediate response to stress signals. It has been shown to induce apoptosis regardless of the presence of anti-apoptotic molecules.

Another splice variant termed Bok-P was found in placental tissue from patients suffering from pre-eclampsia. While Bok-S misses exon 3, Bok-P lacks exon 2. This deletion includes the BH4 domain and parts of the BH3 domain. Bok-P may be the cause for trophoblast cell death in pre-eclampsia, a dangerous pregnancy complication. In pre-eclampsia, typical alterations occur in the maternal kidney and lead to hypertension and proteins in the urine. To date, the cause of this medical condition as well as an appropriate treatment have not been discovered.