By microsequencing a protein, termed IEF SSP 3521, that is upregulated in transformed embryonic lung fibroblasts and using
degenerate PCR primers to screen a transformed embryonic lung fibroblast cDNA library, Honore et al. (1992) obtained a
cDNA encoding STIP1. Sequence analysis predicted that the 543-amino acid hydrophilic protein contains a tetratricopetide
repeat (TPR), a 34-amino acid motif that is repeated at least 6 times in STIP1. STIP1 is homologous to the yeast
stress-inducible mediator of the heat shock response, Sti1. Western blot analysis and 2-dimensional gel electrophoresis
confirmed that STIP1 is expressed as an approximately 61-kD protein. Northern blot analysis showed that STIP1, which is
expressed as an approximately 2.1-kb transcript, is upregulated in transformed cell lines and psoriatic keratinocytes.
Immunofluorescence analysis showed that STIP1 localizes to the Golgi in normal fibroblasts but mainly to the nucleus in
transformed cells.
General function
Intracellular signaling cascade
Comment
Cellular localization
Cytoplasmic, Nuclear
Comment
Ovarian function
Comment
Expression regulated by
FSH
Comment
Clouscard-Martinato C et al 1998 reported the characterization of FSH-regulated genes isolated by mRNA
differential display from pig ovarian granulosa cells.
They have isolated FSH-regulated genes from primary granulosa
cell cultures with or without Follicle Stimulating Hormone (FSH) treatment using
mRNA differential display. mRNA differential display consists of amplification
of partial sequences of cDNAs (150-400 bp) corresponding to 3' ends of cellular
messenger RNAs, and thus, generates 3' expressed sequence tags (3' ESTs). Five
thousand cDNA bands were examined, among which the present authors have
isolated and sequenced 16 different FSH-regulated products. These sequences
were compared with those available in databases. Three of the sequences showed
similarity to identified genes from other species (bovine NADH dehydrogenase
subunit 4, Xenopus chromosome sequence-associated polypeptide E and
transformation-sensitive protein IEF SSP).
Regulation of the corresponding genes has been checked by RT-PCR since most of
these are expressed at a low level.
Ovarian localization
Oocyte, Granulosa
Comment
Expression of heat shock protein70 in pig oocytes: Heat shock response during oocyte growth Lanska V, et al .
The heat shock response of growing and fully-grown pig oocytes was analyzed in vitro by determining heat shock protein70 (HSP70) synthesis under both normal conditions (39 degrees C; 0 and 6h) and after heat shock (43 degrees C; 1, 4 and 6h). The expression of HSP70 in oocytes was detected by immunoblotting analysis. Growing oocytes measuring 80-99mum synthesized a high number of HSP70 without heat shock effect, and these were capable of increasing the synthesis of HSP70 after heat shock to a maximum after 1h. Growing oocytes measuring 100-115mum also synthesized HSP70 without heat shock and after it, but the HSP70 synthesis was not statistically changed by increasing duration of heat shock. In fully-grown oocytes, great amounts of HSP70 were found without heat shock treatment, and the contents of HSP70 significantly decreased after heat shock. These results indicate that growing oocytes are able to synthesize HSP70 after heat shock. This ability declines at the end of the growth period, and fully-grown oocytes are unable to induce HSP70 synthesis after heat shock. HSP70 is synthesized and stored during oocyte growth. The high HSP70 synthesis in non-heat-treated growing oocytes and a great amount of HSP70 in fully-grown oocytes support the hypothesis that HSP70 is important for oocyte growth and maturation.