The turkey prolactin-encoding gene and its regulatory region

Area of Science:

• Molecular Biology
• Genomics
• Endocrinology

Background:

• Prolactin (Prl) is a crucial hormone involved in reproduction and development.
• Understanding the genetic regulation of Prl in avian species like turkeys is important for comparative endocrinology.

Purpose of the Study:

• To isolate and characterize the turkey prolactin (Prl) gene.
• To investigate the regulatory elements controlling turkey Prl gene transcription.

Main Methods:

• Isolation of overlapping prolactin (Prl) lambda clones from a turkey genomic library.
• Determination of gene structure, including exon-intron boundaries.
• Identification of transcription start points using primer extension.
• Bioinformatic analysis to identify potential regulatory DNA sequences, such as estrogen response elements (ERE) and Pit-1/GHF-1 binding sites.

Main Results:

• The turkey Prl gene spans 6.7 kb and comprises five exons.
• Major transcription start points were mapped 51-53 nucleotides upstream of the Met start codon.
• No estrogen response element (ERE) was detected in the gene sequence.
• Two regions homologous to mammalian Pit-1/GHF-1 binding sites were identified.

Conclusions:

• The characterized turkey Prl gene provides a foundation for further studies on avian prolactin.
• Transcription of the turkey Prl gene is likely regulated by Pit-1/GHF-1 transcription factors.
• Regulation appears to be independent of estrogen receptor-mediated pathways, contrasting with some mammalian systems.