Cloning and regulation of the rat activin betaE subunit

Abstract

Using a combination of polymerase chain reaction (PCR) procedures, we have cloned and sequenced the rat activin E subunit cDNA. The putative protein corresponding to the prepro-activin E subunit was predicted to comprise 350 amino acids which, when cleaved between amino acid residues 236 and 237, would yield a mature polypeptide of approximately M r 12 500 with a predicted pI of 5·1. Two cDNA transcripts for activin E were identified; these differed by 738 bp in the 3 -untranslated region. Activin E mRNA transcripts were expressed only in rat liver and lung tissue as assessed by Northern blotting and PCR analysis. Relatively higher levels of both transcripts were found in the liver, whereas the lung contained lower levels that were detectable by PCR only. In situ hybridisation data showed that, within the liver, activin E mRNA was localised to hepatocytes. In vivo treatment with lipopolysaccharide as a means of activating the immune system and the hepatic acute-phase response resulted in stimulated activin E mRNA levels, compared with untreated, control rats. This increased expression was accompanied by a preferential increase in the amount of the long activin E transcript over the shorter transcript. These findings suggested that the two activin E mRNA transcripts may be products of alternative splicing events or use alternative polyadenylation sites which are differentially regulated during inflammation. These data provide evidence of a role for activin E in liver function and inflammation in the rat.

Expression and dimerization of the rat activin subunits betaC and betaE: evidence for the ormation of novel activin dimers

“…Expression of activin E was highly upregulated after 6 h, but declined rapidly thereafter (Lau et al 2000). This induction was also observed in rats treated with lipopolysaccharide (O'Bryan et al 2000) reminiscent of an acute phase response (Moshage 1997). Collectively, these results indicate diverse functions of the activins expressed in the liver.…”

“…The properties of both cDNAs and the encoded polypeptides are summarized in Table 2. The sequence of rat activin subunit E differs from a recently published sequence (O'Bryan et al 2000) by four nucleotide positions, two of which affect the amino acid sequence of the propeptide (amino acid 160 and 161).…”

“…Based on similarity to known activins, two further mammalian subunits, termed activin C and E , have been cloned more recently (Hötten et al 1995, Schmitt et al 1996, Fang et al 1996, O'Bryan et al 2000. So far, however, no biological role for activin C and E has been elucidated.…”

Activins and follistatins: Emerging roles in liver physiology and cancer

“…In line with these observations, elevated beta C immunoreactivity was found in human prostate, testis and liver cancers [87] . Like beta C, also the beta E subunit is highly expressed in the liver, but has been detected at lower levels in several other tissues as well [7,11,88,89] . In the liver of the developing mouse, activin beta E expression could not be detected until the very late stages of embryonic development and peaked at birth [82] .…”

FGFR-1 signaling is involved in spermiogenesis and sperm capacitation

“…The missing 3Ј end was cloned using 3Ј rapid amplification of cDNA ends (RACE), utilizing the FirstChoice TM RLM-RACE kit (Ambion, Texas) as previously described (O'Bryan et al, 2000b;Troutt et al, 1992), using the primers F1701A 5Ј-AGC-CCAATGCACCTATGAG-3Ј, F1701B 5Ј-CTTCCTCCTGTGTGGGAGAG-3Ј and the supplied adaptor primer, AP3Ј. The sites of cellular expression of Snt-2 within the developing testis was determined by Northern blotting using a 1.2 kb (5Ј fragment) Snt-2 specific probe (O'Bryan et al, 1998).…”