Analysis of a polymorphism at STAT5A gene in Agerolese cattle breed

Signal transducers and activators of transcription (STATs) are a 7-member family of latent cytoplasmic transcription factors that mediate actions of a variety of peptide hormones and cytokines within target cells (Darnell et al., 1994). STAT5 is known as a main mediator of growth hormone (GH) action on target genes (Argetsinger and Carter-Su, 1996); it is a key intracellular mediator of prolactin signalling (Wakao et al., 1994). Initially, a single STAT5 gene was identified in sheep but subsequently two forms of STAT5 (STAT5A and STAT5B), encoded by two different genes, have been identified in many species (Herrington et al., 2000). Flisikowski et al. (2003, 2004) described the substitution T→C at position 12,743 within exon 16, which causes a conservative change of the amino acid sequence (Val/Ala) at position 686. The amino acid substitution was shown to modify DNA-binding properties of the STAT5A. The objective of this work is to study the genetic polymorphism of the STAT5A/MslI in a sample of Agerolese cattle breed