cohort : patients delivered at the bnai - zion hospital , haifa , israel , and at the wolfson medical center , holon , israel , were recruited to the study after signing an informed consent , and their placenta were collected after delivery . the cohort was comprised of 9 preeclamptic ( pe ) patients delivered before 37 weeks ( 1 before 34 weeks ), 3 hellp patients delivered before 37 ( 1 delivered before 34 weeks ), 5 preterm delivery ( ptd ) patients delivered before 37 weeks ( 3 before 34 weeks ) and 9 normal pregnant women delivered at term (& gt ; 37 weeks ). preeclampsia was diagnosed according to hypertension of 140 ( systolic ) or 90 ( diastolic ) mmhg developed after 20 weeks of gestation in women who were normotensive before and accompanied by proteinuria of 2 + in a dipstick or 300 mg / dl at 24 hr collection in women with no protein in the urine before pregnancy . hellp was diagnosed as preeclampsia plus two of the following a - c : a ) hemolysis ( lactic dehydrogenase & gt ; 600 iu / l , or serum bilirubin & gt ; 1 . 2 mg / dl , or the presence of schistocytes in the peripheral blood ); b ) increased serum aspartate aminotransfarase concentration (& gt ;= 70 iu / l ); c ) thrombocytopenia ( platelet count & lt ; 100 , 000 / mm3 ). ptd were women who delivered before 37 weeks not due to preeclampsia or iugr but idiopathic preterm delivery . table 1 shows the summary of clinical characteristics of the patient and control groups ( values are mean ± standard deviation ). total rna was extracted from 100 mg placental tissue using trizol reagent ( invitrogen ). rna concentration and purity were monitored by spectrophotometer at 260 / 280 nm ( beckman coulter ) and stored in dnase / rnase - free water until use . the first strand cdna was synthesized with superscript ii rt reverse transcriptase using a oligo ( dt ) 15 ( promega ) as follow : 3 μg of total rna were reverse transcriptized by 200 units of superscript rt using 25 ng of oligo ( dt ) 15 and 0 . 5 mm of dntp mixture at 42 ° c . for 50 min . the sense primer 5 ′- agagatggtgtctagcgccaa - 3 ′ ( seq id no : 3 ), and anti - sense primer 5 ′- cggtcactacggactttgtctt - 3 ′ ( seq id no : 4 ) ( primerbank id 20127486a3 ) were used for real time pcr to amplify pp17 using qpcr syber green ( abgene ™, uk ) on gene amp 5700 sequence detection system ( applied biosystem , usa ). pcr was performed with 2μl cdna , 10μl of x2 qpcr syber green mix and 2 μl of sense and antisense primers ( 70 nm each ). pcr was conducted by one 15 min cycle at 95 ° c . and 40 cycles of two - steps of 15 sec at 95 ° c . and 1 min at 60 ° c . samples were normalized to the level of the ywhaz determined in parallel . following amplification , melt curves were generated to confirm the specificity of each primer pair . the fold increase relative to placenta of a control case was determined by 2 − δδct method and relative expression software tools - rest ( references : ( 1 ) pffafl m . w . a new mathematical model for relative quantification in rel - time rt - pcr , nucleic acids res . ( 2001 ), 29 ; 2001 - 2007 ( 2 ) pffafl mw et al : relative expression software tool ( rest ) for group - wise comparison and statistical analysis of relative expression results in real time pcr , nucleic acids res . ( 2002 ), 30 ; e36 ). pcr products were further analyzed using 2 % agarose gels and visualized with ethidium bromide . cloning the full length pp17 gene , expression in host cells and affinity purification of recombinant pp17 ( rpp17 ) the nucleotide sequence of pp17 with accession no . nm 005817 as shown in fig1 was used for selection and design of two primers to cover the full length of the gene . for cloning the full - length pp17 gene , two primers were designed with the following sequences : sense primer : 5 ′- taatacggatccatgtctgccgacggggc - 3 ′ ( seq id no : 5 ) and anti - sense primer : 5 ′- taagtcgagctcctacttcttctcctccgg - 3 ′ ( seq id no : 6 ). the restriction site sequences of bamh i and sac i were introduced into the sense and antisense primers , respectively . both primers were synthesized by sigma - genosys . 1 ng of pp17 cdna was amplified with 0 . 2 μm of the above mentioned specific primers using the red pcr master mix containing tage dna polymerase , dntp &# 39 ; s and mgcl2 ( larova ). pcr was carried out under the following conditions : 94 ° c . for 2 min once , then 94 ° c . for 30 sec , 55 ° c . for 30 sec and 72 ° c . for 2 min over 35 cycles . a final extension was carried out at 72 ° c . for 4 min followed by storage of the pcr product at 4 ° c . until use . the pcr product was analyzed by agarose gel and revealed the expected size of 1 . 3 kb . a — ligation : the pcr product of pp17 dna was purified by qiaquick pcr purification kit prior to ligation . the expression vector pqe - 30 was purchased from qiagen . both the pqe - 30 ( 0 . 5 μg ) and the purified pcr product dna ( 1 μg ) were digested with bamh i and sac i ( 20 u each ) in nebuffer bamh i and nebuffer sac i , respectively . both enzymes were purchased from new england biolabs ( neb ). an insert : vector ratio of 3 : 1 , 1 : 1 and 1 : 3 was used for ligation of the digested pcr product dna with 50 ng of digested pqe - 30 using 100 u of t4 ligase ( neb ) and t4 ligase buffer for 2 hr at 22 ° c . b — transformation : the ligation mixture was transferred to m15 ( prep4 ) cells ( qiagen ). 10 μl of the ligation mixture were added to 100 μl competent m15 prep4 cells for 10 min in ice and then transferred to a 42 ° c . water bath for 50 sec . after heat shock , the mixture was placed in ice for another 2 min and 900 μl of lb medium were added to the transformation reaction and incubated for 60 min at 37 ° c . with shaking of approximately 225 rpm . 10 - 100 μl of the cells were plated on lb agar plate containing 100 μg / ml ampicillin ( sigma ) and 25 μg / ml kanamycin ( sigma ) for overnight at 37 ° c . c — screening for positive colonies : 20 single colonies grown on the plate were chosen and cultured in 2 ml lb medium containing ampicillin ( 100 μg / ml ) and kanamycin ( μg / ml ) overnight at 37 ° c . with 225 rpm shaking . plasmid dna was purified from each colony culture with wizard plus sv minipreps dna purification system ( promega ). the presence of the pp17 dna insert was tested by pcr as follow : the pcr reaction ( 20 μl volume ) was composed of 1 ng of dna template , 0 . 2 μm of pp17 specific primers ( seq . id . nos . 5 and 6 ) and 10 μl of x2 ready mix for pcr ( bio - lab ltd ). the pcr conditions were as described above . pcr products were separated on 1 % agarose and the dna bands were visualized in a las - 3000 image system ( fuji ). the potential positive clones ( 4 ) were selected according to the calculated size of the pcr product . the final dna sequence of each clone was determined by sequencing carried out in the multi - disciplinary laboratories unit ( rappaport institute of medical science — technion , haifa ). 1 . based on sequence analysis , one bacterial positive clone carrying pp17 cloned in pqe30 vector was selected for expression of the protein and grown in 20 ml of lb medium containing ampicillin and kanamycin at 37 ° c . for overnight with shaking . the culture was mixed 1 : 50 in lb medium containing antibiotics and grown at 37 ° c . until an od 600 of 0 . 6 was reached . the expression of the protein was induced with 1 mm — isopropyl - b - d - thiogalactopyranoside ( iptg ) for 3 hrs at 37 ° c . ( fig3 ). bacterial cells were harvested by centrifugation at 4000 g × 20 min at 4 ° c . the cell pellet was stored until use at − 80 ° c . aliquots were collected before and after induction and pp17 was tested by sds - page followed by gel code staining ( 3a ) and by western blot ( 3b ) using anti - histidine antibodies and visualized by las3000 system to test pp17 expression as a recombinant protein . 2 . purification of pp17 : based on sds - page analysis , the recombinant pp17 was localized in the soluble fraction . the cell pellet was resuspended in lysis buffer containing 20 mm tris - hcl , ph 8 , 150 mm nacl , 5 mm imadizole and protease inhibitor ( roche ) and 10 % glycerol . the cells were disrupted by applying pressure of 1000 psi in minicell french press ( thermo ). soluble proteins were collected and the pellet containing the inclusion bodies was discarded . soluble fraction was filtered through 0 . 25 μm filters and mixed with 1 ml of pre - equilibrated ni - nta agarose ( qiagen ) for 1 hr at rt . first the ni - nta agarose column was washed with 20 ml of wash buffer ( 20 mm tris - hcl , ph 8 . 0 , 300 mm nacl , 20 mm imidazole , pmsf , complete and 10 % glycerol ). bound recombinant pp17 was eluted with 15 fractions of 1 ml of elution buffer ( 20 mm tris - hcl , ph 8 . 0 , 300 mm nacl , 0 . 5 m imidazole , pmsf , complete and 10 % glycerol . pp17 was analyzed by sds - page ( 10 %). positive fractions were combined and dialyzed against tbs ( 20 mm tris - hcl , ph - 8 , 150 mm nacl ) and stored at − 80 ° c . until use . the protein concentration was determined by bradford assay . the purification analysis is shown in fig4 a and 4b . a total of 21 pregnant women participated in the study . placental tissue was analyzed for the expression of pp17 by normal and real time pcr . representative results of regular pcr are shown in fig5 . pp17 was expressed in the placenta of healthy controls and in the pathological cases . quantification of pp17 expression was measured by real time pcr . the expression of pp 17 in placentas obtained from pe and hellp women was compared to that of normal women . the results are shown in fig6 . pp17 was significantly ( p = 0 . 022 ) up - regulated by a factor of 3 . 073 in hellp versus normal women , and was significantly ( p = 0 . 017 ) up - regulated by a factor of 1 . 783 in preeclampsia versus normal .