If you mean a protocol to assess if your line or strain is deficient in mRNA export from the nucleus you can use the protocol descibed in this paper, its relatively easy and the read0out is quite obvious
Germain, H., Na, Q., Cheng, Y.T., Lee, E.K., Huang, Y., Dong, O.X., Gannon, P., Huang, S., Ding, P., Li, Y., Sack, F., Zhang, Y., and Li, X. 2010. MOS11: a new component in the mRNA export pathway. PLoS Genetics. (the full text is available on my profile and web site)