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Fig. 3. Hoxb13 is required for secretion of major ventral prostate proteins. The
lack of ventral secretory protein expression is specific to Hoxb13
homozygous mutants. (A) SDS-PAGE of secretory proteins. Hoxb13
homozygous mutants do not express p25 a 25-40 kDa glycoprotein or p12 a 6 kDa
serine protease inhibitor (lane 3). Hoxd13 mutants do not exhibit
defects in their ventral prostatic secretory protein profile. In the absence
of Hoxd13, one copy of Hoxb13 is sufficient for expression
of both p12 and p25 (lane 4). (B) The Hoxb13 mutation appears to
affect secretory function of only the ventral prostate. SDS-PAGE of secretory
proteins from anterior prostates (AP) ventral prostates (VP). (C)
Hoxb13 homozygous mutant ventral prostates do not produce secretory
protein mRNA. Semi-quantitative RT-PCR using primers for the two major ventral
secretory proteins p12 and p25, reveals absence of these mRNAs in ventral
prostates from Hoxb13 homozygous mutants. Heart and liver RNAs are
used as negative controls, GAPDH is an internal loading control. Molecular
mass markers indicated by bars on the left of A and B are 188, 98, 62, 49, 38,
28, 17, 14, and 6 kDa.