Human epidermal growth factor precursor: cDNA sequence, expression in vitro and gene organization.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Epidermal Growth Factor (EGF) plays a crucial role in cellular processes.
• Understanding the structure and gene organization of EGF precursors is vital for comprehending its function.

Purpose of the Study:

• To isolate and sequence complementary DNA (cDNA) clones encoding the human kidney EGF precursor.
• To elucidate the structural organization and gene structure of the human EGF precursor.

Main Methods:

• Isolation and sequencing of human kidney EGF precursor cDNA clones.
• Transfection of COS-7 cells with the human EGF precursor cDNA.
• Analysis of the human EGF precursor gene's exon-intron organization.

Main Results:

• The human EGF precursor is a 1,207 amino acid protein with a conserved structural organization compared to the mouse homolog (66% sequence identity).
• The precursor is synthesized as a membrane protein with the NH2-terminus exposed extracellularly.
• The human EGF precursor gene spans approximately 110 kilobase pairs and comprises 24 exons, with individual exons encoding distinct functional domains.
• Fifteen exons encode protein segments homologous to other known proteins, suggesting a role for exon duplication and shuffling in its evolution.

Conclusions:

• The human kidney EGF precursor exhibits significant structural similarity to its mouse counterpart.
• The gene structure suggests evolutionary mechanisms like exon duplication and shuffling contributed to the EGF precursor's complex domain organization.