Sialylation in protostomes: a perspective from Drosophila genetics and biochemistry.

Numerous studies have revealed important functions for sialylation in both prokaryotes and higher animals. However, the genetic and biochemical potential for sialylation in Drosophila has only been confirmed recently. Recent studies suggest significant similarities between the sialylation pathways of vertebrates and insects and provide evidence for their common evolutionary origin.

Two isoforms of Drosophila TRF2 are involved in embryonic development, premeiotic chromatin condensation, and proper differentiation of germ cells of both sexes.

The Drosophila TATA box-binding protein (TBP)-related factor 2 (TRF2 or TLF) was shown to control a subset of genes different from that controlled by TBP. Here, we have investigated the structure and functions of the trf2 gene. We demonstrate that it encodes two protein isoforms: the previously described 75-kDa TRF2 and a newly identified 175-kDa version in which the same sequence is preceded by a long N-terminal domain with coiled-coil motifs.

Esterase-like and fibronectin-like polypeptides share similar sex-cell-biased patterns in the gonad of hermaphroditic and gonochoric species of bivalve mollusks.

The mechanism of sexualization of the tubular gonad in seawater bivalves is unknown, and no information regarding the genes involved in this process is yet available, except for the identification of esterase (Est)-like "male-associated polypeptide" in the male gonad of Mytilus galloprovincialis. Our present work reveals distinct protein profiles specific for the testicular or ovarian portion of the ovotestis of Pecten maximus. Two proteins exhibiting testis- or ovary-dependent enrichment in the ovotestis have been identified and partially characterized as Est-like and fibronectin (Fn)-like polypeptides, respectively.

Hsp70 family proteins seem to facilitate allo- and xenotransplantation in the rat brain.

Drosophila neuroectodermal embryonic cells were transplanted into the occipital brain region of adult rats. The first series of experiments used a transgenic strain expressing lacZ to detect the presence of Drosophila cells. The second series used a strain carrying a is lethal (ts403) in the X chromosome; this mutation strongly inhibits the synthesis of heat shock proteins (hsps) and their transport into the nuclei.

Mussel MAP, a major gonad-duct esterase-like protein, is released into sea water as a dual constituent of the seminal fluid and the spermatozoon.

Our interest in the comparative analysis of male reproductive-tract esterases in different animal groups has led us to undertake a detailed study of the Mytilus galloprovincialis male-associated polypeptide (MAP) throughout the mussel gonad-duct tract and at spawning. The results of this work indicate that MAP is a major protein in M. galloprovincialis semen, with dual presence in both sperm cells and cell-free seminal fluid.

Expression pattern of dd4, a sole member of the d4 family of transcription factors in Drosophila melanogaster.

In vertebrates, three members of the d4 gene family code for proteins, which are believed to function as transcription factors and involved in regulation of various intracellular processes. One member of the family, ubi-d4/requiem is ubiquitously expressed gene and two other, neuro-d4 and cer-d4, are expressed predominantly in the neural tissues (Nucleic Acids Res. 20 (1992) 5579; Biochim.