A developmentally regulated gene product from Dictyostelium discoideum shows high homology to human α‐L‐fucosidase

Abstract

A cDNA library of poly(A+)-RNA has been prepared from membrane-bound polysomes of Dictyostelium discoideum and screened for clones hybridizing to mRNA species that encode developmentally regulated proteins. The clone investigated in this paper recognizes a 1.8 kb transcript that accumulates strongly between the growth phase and aggregation stage. Stimulation of cells with pulses of CAMP enhances the accumulation. The amino acid sequence derived from a complete cDNA and from a genomic clone displays extensive sequence identity to human liver a-L-fucosidase. The D. discoideum DNA sequence encodes a 50.5 kDa polypeptide with a hydrophobic signal peptide at the N-terminus. Antibodies against a synthetic peptide corresponding to amino acids 262-275 of the deduced protein sequence recognize a developmentally regulated 50 kDa protein in D. discoideum that is recovered in the particulate fraction.

Disruption of Aldehyde Reductase Increases Group Size in Dictyostelium

“…As shown in Fig. 7, fractionation of both vegetative and 6-h developing cells by differential centrifugation indicated that AlrA was not detectable in the low speed pellet (containing nuclei (57) and cytoskeletons) and the medium speed pellet (containing large organelles such as mitochondria (58, 59) and ribosomes (67,68)). AlrA was apparently confined to the high speed supernatant fraction, which contains cytosolic proteins (66).…”

Regulation of the Discoidin I gamma gene in Dictyostelium discoideum: identification of individual promoter elements mediating induction of transcription and repression by cyclic AMP.

“…Previously, we have identified a short sequence which is necessary for the developmental induction (21) and sufficient for cAMPmediated stimulation (T. May, J. Blusch, and W. Nellen, submitted for publication) of the Dictyostelium alpha-fucosidase gene (22).…”

Identification of a cis-acting element controlling induction of early gene expression in Dictyostelium discoideum.

“…A TATAAA box is positioned at -150 (upstream from the ATG), and several G-rich elements, previously shown to be involved in gene regulation (6,7,26,29) are located within the promoter sequence; the one at -354 is very similar to the upstream activating sequence in the actin 6 and actin 15 genes, and the G box at -286 is reminiscent of a promoter element found in the Pst Cath gene. In contrast to other Dictyostelium promoters, there is no T run (15) close to the transcriptional start site (21), and the 5' untranslated region is unusually rich in G and C residues. The 5' end of the fragment containing the promoter displays an open reading frame terminated by a TAA stop codon and the AATAAA sequence that is used as a polyadenylation signal in most other eucaryotes.…”

“…Accumulation of A11H2 mRNA could first be detected on Northern blots after 4 h of development. Expression levels reached a peak at 6 h and then slowly declined during the later developmental stages (21). As determined by run-on transcription assays, the AllH2 gene is regulated on the transcriptional level.…”

“…The Dictyostelium A11H2 gene, which encodes an afucosidase, is strictly regulated during development: on the RNA level, expression is not detectable in vegetative cells; induction is observed at about 4 h of development, and maximal amounts of the message are seen at 6 h. Apparently, cAMP is involved in the differential regulation of the gene (21). Because of the strong developmental induction, we have used the A11H2 promoter to investigate the regulation of early gene expression in D. discoideum.…”