sentence: Since there are no antibodies against Ssh1p , we assessed expression of the fusion protein in the SSH1 / SSH1-CPLV strain by comparing it to the amount of Sec61-CPLV in the heterozygous SEC61 / SEC61-CPLV strain using an antibody against CPLV that we had raised and against Pdi1p as an internal marker , We found that expression levels of both fusion proteins were comparable ( Figure 3A , right ) .