TASK DEFINITION: In this task, you are given a passage which has a question and the context. You have to generate an answer to the question based on the information present in the context.
PROBLEM: Context: To test whether extension of the C-terminus of human chorionic gonadotropin (hCG) alpha-subunit (halpha) alters the bioactivity of the recombined alphabeta heterodimer.', 'The stop codon of halpha was mutated to produce a 24 amino acid extension.', 'The extended halpha (alpha(+24)) was co-expressed with hCGbeta in COS-7 cells and the receptor binding and in vivo bioactivity of the secreted hormone was compared with its wild-type counterpart.', 'This extension did not impair the binding of hCG to rat LH/CG receptors and provoked a sixfold reduction in its stimulatory activity of testosterone secretion in rat Leydig cells.\Question: Does human chorionic gonadotropin with C-elongated alpha-subunit retain full receptor binding and partial agonist activity?

SOLUTION: The extension of alpha by itself does not lead to inhibition of the alphabeta heterodimer to LH receptors but the structure of the extension appears to play an important role. It is thus possible that one-chain hCG chimeras with the beta N-terminus fused to the alpha C-terminus might be active.

PROBLEM: Context: Protein kinase D (PKD or PKD1) is a serine/threonine protein kinase that has been shown to play a role in a variety of cellular processes; however, the function of PKD1 in the skin has not been fully investigated. The balance between proliferation and differentiation processes in the predominant cells of the epidermis, the keratinocytes, is essential for normal skin function.', 'To investigate the effect of PKD1 deficiency on proliferation and differentiation of epidermal keratinocytes.', 'We utilized a floxed PKD1 mouse model such that infecting epidermal keratinocytes derived from these mice with an adenovirus expressing Cre-recombinase allowed us to determine the effect of PKD1 gene loss in vitro. Proliferation and differentiation were monitored using qRT-PCR, Western blot, transglutaminase activity assays, [3H]thymidine incorporation into DNA and cell cycle analysis.', 'A significant decrease in PKD1 mRNA and protein levels was achieved in adenoviral Cre-recombinase-infected cells. Deficiency of PKD1 resulted in significant increases in the mRNA and protein expression of various differentiation markers such as loricrin, involucrin, and keratin 10 either basally and/or upon stimulation of differentiation. PKD1-deficient keratinocytes also showed an increase in transglutaminase expression and activity, indicating an anti-differentiative role of PKD1. Furthermore, the PKD1-deficient keratinocytes exhibited decreased proliferation. However, PKD1 loss had no effect on stem cell marker expression.\Question: Does protein kinase D1 deficiency promote differentiation in epidermal keratinocytes?

SOLUTION: Cre-recombinase-mediated knockdown represents an additional approach demonstrating that PKD1 is an anti-differentiative, pro-proliferative signal in mouse keratinocytes.

PROBLEM: Context: Existing dogma that a female is born with fixed number of eggs was challenged by the detection of stem cells in adult mammalian ovary. Data has accumulated in support of ovarian stem cells (OSCs) proliferation, maintenance in culture, formation of germ cell nests and differentiation into oocytes and primordial follicle assembly using different strategies.', 'Flow cytometry analysis identified >8\xa0μm OSCs which are DDX1 positive and are considered equivalent to spermatogonial stem cells (SSCs) in testis. Analysis of both ovarian and testicular smears obtained after enzymatic digestion has led to the identification of an additional stem cell population termed very small embryonic-like stem cells (VSELs). VSELs and OSCs/SSCs differ from each other in their size and OCT-4 expression. VSELs express pluripotent markers including nuclear OCT-4 whereas OSCs/SSCs express cytoplasmic OCT-4 suggesting a differentiated state. VSELs can be studied by flow cytometry as small sized cells which are LIN-/CD45-/Sca-1+. We have reported 0.02\u2009±\u20090.008, 0.03\u2009±\u20090.017 and 0.08\u2009±\u20090.03\xa0% of total cells as VSELs in normal, chemoablated and after FSH treatment to chemoablated mouse ovary.\Question: Are ovarian stem cells always accompanied by very small embryonic-like stem cells in adult mammalian ovary?

SOLUTION:
VSELs have remained poorly studied till now because of their very small size and rare occurrence. Spinning cells obtained after enzymatic digestion of ovarian tissue at a speed of 1000G (rather than 1200 rpm) throughout processing allows reliable detection of the VSELs by flow cytometry. VSELs exist in aged, chemoablated and non-functional ovary and providing a healthy niche to support their function offers an interesting strategy to manage infertility.