题目内容：

分子生物学文章求翻译
NIPP1 is a ubiquitous nuclear protein that is required
for spliceosome assembly. We report here that the phos-
phothreonine-binding Forkhead-associated domain of
NIPP1 interacts with the cell cycle-regulated protein
Ser/Thr kinase MELK (maternal embryonic leucine zip-
per kinase). The NIPP1-MELK interaction was critically
dependent on the phosphorylaton of Thr-478 of MELK
and was increased in lysates from mitotically arrested
cells. Recombinant MELK was a potent inhibitor of an
early step of spliceosome assembly in nuclear extracts.
This splicing defect was also seen with a kinase-dead
mutant but was absent after mutation (T478A) of the
NIPP1 binding site of MELK, indicating a mediatory
role for NIPP1. Our data suggest that MELK has a role in
the cell cycle-regulated control of pre-mRNA splicing.