Structure of the rat prolactin gene

Area of Science:

• Molecular Biology
• Genetics
• Endocrinology

Background:

• Understanding gene structure is crucial for deciphering gene regulation and function.
• The rat preprolactin gene encodes a key hormone involved in lactation and other physiological processes.

Purpose of the Study:

• To elucidate the complete organization and nucleotide sequence of the rat preprolactin gene.
• To identify the genomic DNA fragments containing prolactin sequences and analyze their structure.

Main Methods:

• Analysis of pituitary cDNA inserts from plasmids to determine the preprolactin coding sequence.
• Restriction endonuclease digestion (Eco RI) of rat chromosomal DNA followed by size fractionation and hybridization with a prolactin cDNA probe.
• Isolation and sequencing of specific genomic DNA fragments from a cloned rat DNA library.

Main Results:

• The complete 681-nucleotide coding sequence of rat preprolactin was determined, including flanking regions.
• Prolactin genomic sequences were localized to 6.0-, 3.9-, and 2.9-kilobase fragments.
• Sequencing of cloned fragments revealed two coding regions (180 and 189 nucleotides) separated by a 597-nucleotide intervening sequence, with at least one additional intervening sequence upstream.

Conclusions:

• The rat preprolactin gene contains multiple intervening sequences, indicating a complex genomic structure.
• Hybridization experiments suggest the presence of repetitive DNA sequences within the intervening sequences of the prolactin gene.
• This detailed structural information provides a foundation for further studies on prolactin gene regulation and evolution.