SUPPLEMENTARY MATERIAL Jens Mattow, Ilja Demuth, Gisela Haeselbarth, Peter R. Jungblut, Joachim Klose Selenium-binding protein 2, the major hepatic target for acetaminophen, shows sex differences in protein abundance Electrophoresis, submitted.

Mother: CalzinatoFather: Aarhus Mother: AarhusFather: Calzinato Mother: CalzinatoFather: Aarhus Mother: AarhusFather: Calzinato Male 1 Female 1Female 2 Female 3Female 4 Female 5 Female 6 Male 1Male 3Male 2 Male 1Male 2Female 1Female 2Female 3Female 4Female 5Female 6 Female 1Female 2Male 1Male 2Male 3Male 4Male 5 Family 1 Family 2 Family 3 Family 4 Parents F 1 (CxA) Hybrids Parents F 1 (AxC) Hybrids Parents F 1 (CxA) Hybrids Parents F 1 (AxC) Hybrids Females vs. Males 5216* 5205* 4303* 4301* * 6805, 6809, 7814*, 8810*

Figure legend Silver-stained 2-DE patterns of cytosolic liver proteins were investigated in 8 parental mice (4 females; 4 males) of 2 subspecies, namely Mus musculus musculus (inbred strain: Calcinato B) and Mus musculus domesticus (inbred strain: Aarhus), as well as in their offspring (25 F 1 hybrids; 14 females; 11 males). The primary goal of this analysis was to identify strain-specific protein variants, which reveal a mode of inheritance compatible with the concept of genomic imprinting. In this context, the protein patterns of the parental mice (2 replicate gels per animal) were compared with each other to elucidate strain- as well as sex-dependent protein variations. The figure depicts sectors from the protein patterns of all 33 mice investigated. The 10 protein spots labeled showed very low intensities in female mice (left side), but high intensities in males (right side). Seven of these spots (marked by asterisks) were unambiguously identified as SBP2 by MALDI-MS. The remaining 3 protein spots (SSP5514, SSP6805, SSP6809) most likely represent additional SBP2 variants, but were not analyzed by MS, due to their absence in preparative CBB G250 stained 2-DE gels. Edman degradation revealed that SSP6613 represents an N-terminally truncated SBP2 variant, which lacks the amino acids of the full-length protein. Similarly, protein spots SSP5216 and SSP5205 were identified as SBP2 variants lacking the amino acids and 1-225, respectively. Edman degradation of SSP8810 did not reveal any sequence data suggesting that this protein spot represents an N-terminally blocked full-length SBP2 variant. For reasons of clarity the spot labels are abbreviated, e.g. protein spot SSP8810 is designated as Please note that only the parental mice were analyzed in detail to elucidate sex- dependent protein variations. However, reproducible sex differences in SBP2 abundance were also detected in the 25 F 1 hybrids.