Induction of proliferation of neuroretina cells by long terminal repeat activation of the carboxy-terminal part of c-mil.

Abstract

Expression of the P100gag-mil protein of avian retrovirus MH2 in cultured chicken embryo neuroretina cells was previously shown to result in the proliferation of normally quiescent cell populations. We show here that long terminal repeat activation of the carboxy terminus of the c-mil gene is sufficient to induce neuroretina cell proliferation.

A novel oncogene related to c-mil is transduced in chicken neuroretina cells induced to proliferate by infection with an avian lymphomatosis virus.

“…Hence, the transduced portion of c-Rmil, which corresponds to -1/10 of the spliced gene, is sufficient for the mitogenic property of the IC1O virus. This is in agreement with previous data showing that LTR-activation of the COOH-terminal portion of c-mil results in NR cell proliferation (Dozier et al, 1987). By analogy with other members of the serine/threonine kinase oncogene family (Beck et al, 1987), it is likely that the transduced portion of c-Rmil also represents the COOH-terminal portion of this gene.…”

Evidence for the induction of casein kinase II in bovine lymphocytes transformed by the intracellular protozoan parasite Theileria parva.

“…For example, an antichicken Mil antibody (Dozier et al, 1987) revealed the presence of equal amounts of a broad protein band of 72-74 kDa in infected and uninfected cells (data not shown). For example, an antichicken Mil antibody (Dozier et al, 1987) revealed the presence of equal amounts of a broad protein band of 72-74 kDa in infected and uninfected cells (data not shown).…”

“…Because Raf and PKC may lie upstream in a pathway leading to CKII activation, we compared levels of these enzymes in uninfected and T.parva-transformed lymphocytes, but were unable to detect any differences in antigen levels and functional activity, respectively. For example, an antichicken Mil antibody (Dozier et al, 1987) revealed the presence of equal amounts of a broad protein band of 72-74 kDa in infected and uninfected cells (data not shown).…”

Alternative splicing of RNAs transcribed from the chicken c-mil gene.

“…It has been shown that the viral P100gag-mi fusion protein is associated with a serine-threonine kinase activity in vitro (14), whereas little is known about the physiological function of the c-mil gene. Recently, we have shown that upon long terminal repeat activation, the 35-kDa carboxyl terminus encoded by c-mil is able, like P1009'-`1 (1), to induce proliferation of avian neuroretinal cells (5). To gain insight into the biological activity of the c-mil gene, we undertook to isolate chicken c-mil cDNAs.…”

“…To ensure the selection of cDNAs containing the entire coding capacity of the c-mil gene, positive clones were subsequently screened by using a 300-base-pair (bp) PvuII fragment (containing the initiation codon) of a human cDNA clone (2,5). Two positive phages containing a 3.1-kilobase-pair (kbp) EcoRI insert were purified, subcloned into plasmid pKH47, and analyzed by restriction mapping (Fig.…”