Porcine stem cell factor/c-kit ligand: its molecular cloning and localization within the uterus

Stem cell factor (SCF), or c-kit ligand, is a multipotent growth factor that has been implicated in an important role in various aspects of animal development, including maintenance of the viability of primordial germ cells. A porcine SCF (pSCF) cDNA was generated from porcine uterine endometrial mRNA by reverse transcriptase-polymerase chain reaction (RT-PCR), and its nucleotide sequence was determined. The 952-bp pSCF cDNA contained an open reading frame encoding 274 amino acids. The deduced amino acid sequence of pSCF is approximately 86%, 83%, and 82%, identical to human, rat, and mouse SCFs, respectively; and it contains the four conserved cysteine residues and Asn-linked glycosylation sites. One additional amino acid was identified in pSCF, Glu130, which is not in the human (hSCF), rat (rSCF), or mouse (mSCF) sequences. Northern analysis of poly(A)+ RNA obtained from Day 16 pregnant endometrium revealed a transcript of approximately 6.5 kb. The size of this transcript is consistent with the size of full-length SCF mRNA, and the occurrence of alternatively spliced pSCF mRNAs were not detected by RT-PCR/Southern hybridization analysis of endometrial and ovarian total cellular RNA (tcRNA). Porcine SCF mRNA has been localized by in situ hybridization in porcine endometrial stromal tissue. Pregnancy does not appear to be a prerequisite for pSCF mRNA expression in endometrial tissue since it was detectable in tissue and tcRNA obtained from pregnant and nonpregnant gilts. The biological significance of uterine pSCF expression is currently unclear, but it probably participates in intracellular communication within the uterus.