Jk. Hitzler et al., Expression patterns of the hepatic leukemia factor gene in the nervous system of developing and adult mice, BRAIN RES, 820(1-2), 1999, pp. 1-11
Hepatic leukemia factor (HLF) is a bZIP transcription factor related to the
CES-2 protein, which controls apoptosis of the NSM serotoninergic neurons
in Caenorhabditis elegans. Ectopic expression of HLF as an E2A-HLF fusion p
rotein in t(17;19)-positive human pro-B cell acute lymphoblastic leukemias
is believed to promote malignancy by interfering with apoptosis, While HLF
has been linked to malignancies of the lymphoid system, it is not normally
expressed in these cells. Rather, HLF transcripts are detected in the liver
, kidney, lung and adult nervous system by Northern blotting. Despite the l
inks to cell death, little is known of the distribution or function of HLF
in the adult and developing mammalian nervous system. Therefore, we cloned
mouse Hlf and studied its expression by in situ hybridization. During embry
onic brain development, Hlf expression was restricted to the anterior pitui
tary and meninges. By early postnatal life, Hlf was highly expressed in som
atosensory cortex, thalamic nuclei, and structures arising from ectodermal
placodes. Subsequently, Hlf expression increased in the central nervous sys
tem and was found throughout the brain by adulthood. In the developing pitu
itary gland, Hlf was highly expressed in the rostral tip of the anterior lo
be. This pattern is similar to that of Tef, an Hlf-related bZIP protein. Ho
wever, while Tef is expressed in the anterior pituitary of the adult mouse,
Hlf was detected in both the anterior and posterior pituitary. Hlf express
ion was not associated with cells undergoing programmed cell death in the n
ervous system. Hlf expression increased markedly with synaptogenesis and wa
s coincident with barrel formation revealed by cytochrome oxidase staining.
Together, these data suggest that Hlf plays a role in the function of diff
erentiated neurons in the adult nervous system rather than programmed cell
death. (C) 1999 Published by Elsevier Science B.V. All rights reserved.