Inhibitor profiles of alkaline phosphatases in bovine preattachment embryos and adult tissues.
J Histochem Cytochem
; 50(3): 415-22, 2002 Mar.
Article
em En
| MEDLINE
| ID: mdl-11850443
ABSTRACT
The alkaline phosphatases are a small family of isozymes. Bovine preattachment embryos transcribe mRNA for two tissue-specific alkaline phosphatases (TSAP2 and TSAP3) beginning at the 4- and 8-cell stages. Whereas no mRNA has been detected in oocytes, there is maternally inherited alkaline phosphatase activity. It is not known which isozyme(s) is responsible for the maternal activity or when TSAP2 and TSAP3 form functional protein. No antibodies are available that recognize the relevant bovine alkaline phosphatases. Therefore, sensitivity to heat and chemical inhibition was used to separate the different isozymes. By screening tissues, it was determined that the bovine tissue-nonspecific alkaline phosphatase (TNAP) is inactivated by low temperatures (65C) and low concentrations of levamisole (<1 mM), whereas bovine tissue-specific isozymes require higher temperatures (90C) and levamisole concentrations (>5 mM). Inhibition by L-homoarginine and L-phenylalanine was less informative. Cumulus cells transcribe two isozymes and the pattern of inhibition suggested heterodimer formation. Inhibition of alkaline phosphatase in bovine embryos before the 8-cell stage indicated the presence of only TNAP. At the 16-cell stage the pattern was consistent with TNAP plus TSAP2 or -3 activity, and in morulae and blastocysts the pattern indicated that the maternal TNAP is fully supplanted by TSAP2 or TSAP3.
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Base de dados:
MEDLINE
Assunto principal:
Bovinos
/
Embrião de Mamíferos
/
Fosfatase Alcalina
/
Inibidores Enzimáticos
/
Isoenzimas
Limite:
Animals
Idioma:
En
Ano de publicação:
2002
Tipo de documento:
Article