Author/Editor		Bowen, ID; Morgan, SM
Title		Non-apoptotic programmed cell death in the salivary glands of the metamorphosing blow-fly Calliphora vomitoria
Type		članek
Source		In: Cestnik V, Pogačnik A, editors. Referati 6. Zavrnikovega spominskega sestanka; 1995 nov 9-11; Lipica. Ljubljana: Veterinarska fakulteta,
Publication year		1997
Volume		str. 15-26
Language		eng
Abstract		During metamorphosis the salivary glands of the blow-fly undergo programmed cell death. Data is presented indicating that this programmed cell death does not in many respects emulate classical apoptosis. The cells are seen to vacuolate and swell rather than condense and shrink. There appears to be a transient enhancement in autophagy and an increase in acid phosphatase activity. This is followed by the characteristic appearance of ribosomal and extracisternal sources of the enzyme leading to autolysis. There apperars to be no lysosomal leakage of acid phosphatase. As in apoptosis the mitochondria persist until the cell fragments. The nucleus however does not show the distinct chromatin margination and blebbing that is typical of apoptosis. On entering the post-feeding period the larvae come to rest and the polytene salivary gland cells show a significant increase in DNA synthesis followed closely by a surge of mRNA synthesis accompanied by increasing protein production. During this prelude to cell death the new mRNA gives rise to at least 10 new patiens. The first new proteins having a MWt between 30 and 100kD appear by day 8 of the life-cycle and a number persist until the advent of cell death on day 9. Other new proteins appear in a cascade of production during day 8 and in vitro translation of mRNA produced at this time shows a new 55kD protein appearing before cell destruction. Significantly no evidence of DNA degeneration or laddering associated with classical apoptosis was observed, on the contrary considerable DNA synthesis in the form of chromosomal endoduplication or "genomic amplification" was seen; selective gene expression being apparently controlled at translational level. Overall the results strongly suggest a synthetically mediated programmed cell death in the metamorphosing salivary glands of the blow-fly which is distinct from apoptosis.
Descriptors		CELL DEATH SALIVARY GLANDS BUTTERFLIES