Mutants of embryonal carcinoma cells defective in the expression of embryoglycan

Area of Science:

• Developmental Biology
• Glycobiology
• Cancer Cell Biology

Background:

• Embryonal carcinoma cells (ECCs) express specific carbohydrate epitopes, such as the developmentally regulated carbohydrate epitope of teratocarcinoma cells (TEC-1).
• Understanding the genetic basis of ECC surface carbohydrates is crucial for deciphering their developmental roles and potential as cancer biomarkers.

Purpose of the Study:

• To isolate and characterize mutants of embryonal carcinoma cells defective in TEC-1 epitope expression.
• To identify genes involved in the synthesis of embryoglycan and assess its necessity for ECC phenotype.

Main Methods:

• Single-step selection using a TEC-01 antibody-ricin conjugate to isolate TEC-1 deficient mutants from mutagenized P19X1 and P19S1801A1 cells.
• Somatic cell hybridization to analyze complementation groups and gene mapping.
• Characterization using monoclonal antibodies, lectins, Sephadex G-50 chromatography, and assessment of differentiation and tumorigenicity.

Main Results:

• Three recessive mutant cell lines were isolated, belonging to at least two complementation groups.
• Mutants displayed unique binding patterns with antibodies and lectins, indicating distinct defects in glycopeptide synthesis.
• One mutant lacked embryoglycan and associated carbohydrate structures but retained ECC morphology, aggregation, differentiation, and tumorigenicity.

Conclusions:

• The study identified three genes involved in embryoglycan synthesis, including a potential fucosyltransferase gene.
• Embryoglycan is not essential for maintaining the fundamental properties of the embryonal carcinoma cell phenotype, including differentiation potential and tumorigenicity.