Tissue-specific expression of the heat shock protein HSP27 during Drosophila melanogaster development.

Abstract

Abstract. The alpha-crystallin-related heat shock (stress) protein hsp27 is expressed in absence of heat shock during Drosophila melanogaster development.Here, we describe the tissue distribution of this protein using an immunoaffinity-purified antibody. In embryos, hsp27 translated from maternal RNA is uniformly distributed, except in the yolk. During the first, second, and early third larval stages, hsp27 expression is restricted to the brain and the gonads. These tissues are characterized by a high level of proliferating cells. In late third instar larvae and early pupae, in addition to the central nervous system and the gonads, all the imaginal discs synthesize hsp27. The disc expression seems restricted to the beginning of their differentiation since it disappears during the second half of the pupal stage: no more hsp27 is observed in the disc-derived adult organs. In adults, hsp27 is still present in some regions of the central nervous system, and is also expressed in the male and female germ lines where it accumulates in mature sperm and oocytes. The transcript and the protein accumulate in oocytes since the onset of vitellogenesis with a uniform distribution similar to that found in embryos. The adult germ lines transcribe hsp27 gene while no transcript is detected in the late pupal and adult brain. These results suggest multiple roles of hsp27 during Drosophila development which may be related to both the proliferative and differentiated states of the tissues.

Hsp27 functions as a negative regulator of cytochrome c-dependent activation of procaspase-3

“…Of signi®cance is the dissociation that certain apoptotic signals conferred by DNAdamage, i.e., exposure with IR, relieve the interaction of Hsp27 and cas-3, and thereby cas-9-mediated cleavage of cas-3. Hsp27 has been implicated in the development of marginal discs in Drosophila (Pauli et al, 1990). Other studies have implicated Hsp27 in di erentiation of embryonal carcinoma and stem cells (Stahl et al, 1992), B lymphoma cells (Spector et al, 1992), osteoblasts and normal T cells (Chaoufour et al, 1996;Esposito et al, 1994).…”

The Hsp27 gene is not required for Drosophila development but its activity is associated with starvation resistance

“…During the Drosophila larval development, Hsp27 is expressed primarily in the brain and gonads (Pauli et al 1990;Michaud et al 1997). In the adult tissues it is localized in the Drosophila central nervous system and the germ line cells of both males and females.…”

Multiple Developmental Requirements of Noisette, the Drosophila Homolog of the U2 snRNP-Associated Polypeptide SF3a60

“…Embryos and tissues were prepared as described by Pauli et al (44) and Pennetta and Pauli (46). Methanol washing was omitted for testes stained against NOI.…”