Gene expression of human sperm component related to A4 amyloid precursor protein

Neurobehavioral development, adult openfield exploration and swimming navigation learning in mice with a modified beta-amyloid precursor protein gene

The processing of beta-amyloid precursor protein (betaAPP) and its metabolites plays an important role in the pathogenesis of Alzheimer's disease (AD) and Down's syndrome. The authors have reported elsewhere that a targeted mutation resulting in low expression of a shortened betaAPP protein (betaAPP(delta/delta)) entails reduced learning abilities. Here the authors investigate whether these effects were caused by postnatal developmental actions of the altered protein. The authors examined 35 mice carrying the betaAPP(delta/delta) mutation for somatic growth and sensorimotor development during the first 4 postnatal weeks (pw) and compared them with 31 wildtype litter-mates. Thereafter, the same mice were tested at about 10 weeks of age for openfield behavior and for swimming navigation learning. Mutant mice showed both transient and long-lasting deficits in development. Body weight deficit started to emerge at postnatal day (pd) 12, peaked with a 15.1% deficit at pd 27 and lasted until pw 33-37. Significant transient deficits in mutant mice during sensorimotor development were observed in three time windows (pd 3-10, pd 11-19 and pd 20-27), long-lasting effects, manifest at pw 8-12 and pw 33-37, emerged at any of the three periods. In the adult mice, exploratory activity of betaAPP mutants in the openfield arena was severely reduced. In the Morris water maze task, mutant mice showed moderate escape performance deficits during the acquisition period but no impairment in spatial memory. The authors conclude that a defective betaAPP gene impairs postnatal somatic development, associated with transient as well as long-lasting neurobehavioral retardation and muscular weakness. Comparison with earlier data suggests that early postnatal handling may attenuate some of the non-cognitive performance deficits in the water maze. Further, the manifestation and time course of behavioral yet not neuropathological symptoms in betaAPP mutant mice resemble in some aspects those of the human Down's syndrome.

Identifying differential gene expression in monoterpene-treated mammary carcinomas using subtractive display

Monoterpene-induced/repressed genes were identified in regressing rat mammary carcinomas treated with dietary limonene using a newly developed method termed subtractive display. The subtractive display screen identified 42 monoterpene-induced genes comprising 9 known genes and 33 unidentified genes, as well as 58 monoterpene-repressed genes comprising 1 known gene and 57 unidentified genes. Several of the identified differentially expressed genes are involved in the mitoinhibitory transforming growth factor beta signal tranduction pathway, as demonstrated by isolation of the mannose 6-phosphate/insulin-like growth factor II receptor and the transforming growth factor beta type II receptor. The monoterpene-induced/repressed genes indicate that apoptosis and differentiation act in concert to effect carcinoma regression. Apoptosis is suggested by the cloning of a marker of programmed cell death, lipocortin 1. Consistent with a differentiation/remodeling process occurring during tumor regression, subtractive display identified YWK-II and neuroligin 1. Thus far, of the cDNAs putatively identified as differentially expressed in this complex in situ carcinoma model, 5 were tested, and each one has been confirmed to be differentially expressed. Additionally, many of the identified known genes are expressed as rare transcripts and exhibit small but significant changes in abundance. Together, these points demonstrate the unique utility of this new gene expression screen to identify altered gene expression in a complex in vivo environment.

A human amyloid precursor-like protein is highly homologous to a mouse sequence-specific DNA-binding protein

From a cDNA sequence, we have deduced the amino acid sequence for a human amyloid precursor-like protein (APPH) with > 92% identity to the CDEI binding protein (CDEBP) of the mouse and the fragmentary rat protein YWK-II of unknown function. Expression of APPH was found in all tissues examined. A striking homology of APPH to human amyloid precursor protein (APP) was observed. Overall identity accounts for 52.7%. However, there are three domains of APPH with remarkably higher similarities, corresponding to amino acid sequence positions 47-204 (76.6%), 308-567 (67.7%), and 694-763 (69.9%). Using an APPH antiserum, we localized APPH in nuclei of human interphase cells and found an increased synthesis of APPH in mitotic cells. Our results indicate that the highly conserved proteins human APPH, mouse CDEBP, and rat YWK-II are apparently homologues of a CDEI binding protein with indispensible function in mammalian genome segregation.

Expression of a gene encoding a specific human sperm protein in Chinese hamster ovarian cells

The cDNA (RSD-2) encoding a human sperm protein (YWK-II) was isolated from a rat testis lambda gt11 expression library. Its nucleotide sequence was determined. The deduced polypeptide showed high identity with the transmembrane-cytoplasmic domains of A4 amyloid precursor protein of Alzheimer's disease. The RSD-2 was inserted into the EcoRI site of the pSV2-EP vector to construct the pSVRS-2 vector. Chinese hamster ovarian (CHO-dhfr) cells were cotransformed with pSV2-neo and pSVRS-2. mRNA and chromosomal DNA prepared from the transformed cells interacted with [32P]RSD-2 as probe by dot hybridization. The production of the YWK-II protein was determined by staining with the YWK-II mAb by an indirect immunofluorescence technique. There was marked staining of the cytoplasm. The RSD-2 cDNA encoding the YWK-II sperm was expressed in the transformed CHO cells. The pSV2-EP vector and the CHO cell expression system can be utilized to produce sperm proteins for antifertility studies.