Area 51: Excalibur-6 (17 page)

Garlin continued. "You age because as you lose telomeres in your cells, your body is like a clock winding down. Eventually you will not have enough good cells to perform some essential task somewhere in your body and one of your vital systems will fail.

"We first became aware of this about fifty years ago when the geneticists Paul Hermann Muller and Barbara McClintock discovered that the telomeres keep chromosomes from fusing end to end, which could lead to chromosome breakage and loss as cells divide. But not only do they keep cells from fusing, they maintain the integrity of the cell itself. This is vital when you start considering the basic gene structure of the human."

Duncan rubbed her arm over the puncture marks, noting that even the latest one was fading. "Why do we run out of telomeres? If they're so important, it seems that the body would make them in order to protect itself."

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"Good question," Garlin said. "And it brings up an interesting paradox. To make telomeres, you need an enzyme called telomerase. Normal cells, however, for some reason after birth, don't make telomerase. In fact, the only time we've managed to discover telomerase synthesis inside the human body after birth is in cancer cells. That's one of the reasons why it's so hard to kill cancer."

Duncan frowned. "That doesn't make sense. The enzyme we need for longer life is only produced by cancer, which kills us?"

"This is still a relatively new field," Garlin said. "We have started at the very basics. In the seventies we first studied telomeres in protozoan ciliates, single-celled organisms that propel themselves with hairlike projections called cilia, rather than in mammalian cells. At that time, ciliates were much easier to work with because they have many more telomeres per cell than do mammalian cells. These organisms have two nuclei, and during the formation of the larger of these, the so-called macronucleus, the chromosomes break up into fragments that then replicate, producing from twenty thousand to as many as ten million pieces of DNA, each of which becomes capped at both ends by telomeres. In contrast, a human cell has only ninety-two telomeres, two for each of the forty-six chromosomes."

"But we've mapped human DNA," Duncan noted. Something about what Garlin had just said bothered her, but she couldn't put her finger on it exactly and she forgot about it as he continued.

"Only very recently," Garlin said. "Bear with me. I want you to understand this.

As study in this field progressed, some surprising things were learned.

Elizabeth Blackburn of the University of California, San Francisco, in the early seventies discovered something quite strange about the molecular regions around the telomere. She found that the sequence

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for telomeres was very short and repeated numerous times, around sixty. This was surprising because at that time the only DNA that had been examined closely—in bacteria and viruses—did not have repeated sequences.

"Expanding to other organisms, other researchers found the same thing—a repeating code in the telomeres. Yeast for example. This led researchers to believe all telomeres were like this. When we finally isolated the first human telomere at Los Alamos, we found a repeating sequence TTAGGG— where the T stands for thymine, the A for adenine, and the G for guanine. What was strange was that all other telomeres— the ciliates, yeast, etc., only had thymine and guanine."

"Why are we different?" Duncan asked. She wondered why he was giving her so much information—first about the new Majestic, and now about this. It was as if he felt she had some information that he expected her to give in return. She realized it was a subtle interrogation technique, one Mike Turcotte might have used.

"Good question," Garlin said. "We'll get to that. Not only do telomeres protect cells from degrading and losing chromosomes, we found they did other things, much more subtle. By extending the ends of the chromosomes with repetitive, noncoding DNA, they prevent the gradual loss of genetic information that would otherwise result from a quirk in the way DNA is replicated. The polymerase enzyme that copies the DNA can't reproduce both strands of the double-helical molecule all the way to the ends. As a result, chromosomes would get progressively shorter with every cell division and essential genes would gradually be eroded. This doesn't happen because the cells can add telomeric DNA to the incompletely replicated ends of the chromosomes."

"In other words," Duncan said, "it keeps our gene pool in line."

"Right. The yeast work showed that when linear DNAs

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tipped with ciliate telomere sequences are put into yeast cells, they subsequently acquire yeast telomere sequences. This indicated that the yeast was able to add sequences de novo to chromosomes."

Duncan held up her hand as she tried to follow. "Are you saying the telomere changed to adapt to the new cells?"

"Yes."

She knew what Garlin was telling her was unusual and she also knew he was leading up to something about what the Grail had done to her.

"Telomerase," Garlin continued, "is unlike all other enzymes we've studied. In addition to protein, it contains an RNA component, which serves as the template for synthesizing the telomere repetitions and the reproduction of the genetic makeup of the host. This suggests that the enzyme might be an intermediate in the evolution from the RNA world to the current world of DNA and protein."

"That's why unicellular organisms are basically immortal," she said. "Because they have telomerase, they can replenish their DNA that would otherwise be lost every time the cell divided."

"Correct," Garlin said. "And why humans aren't. Since we don't have telomerase, our telomeres shorten every time our cells divide. Sperm and egg cells have the longest telomeres. We start dying the second we are conceived and our cells start dividing and multiplying."

"Why?" Duncan asked.

"That's the thing that's puzzled researchers. If a single cell organism can have telomerase, why can't we? And it's more than just about dying, we're also talking about repairing cell damage."

Duncan's hand went to her lower chest where Yakov's bullet had killed her. There was no sign of the wound even though less than a day had passed since she had been shot.

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"Telomeres support the activity of the RAD9 gene," Garlin said. "RAD9 halts the growth of cells whose DNA has been damaged, which suggests that telomeres are part of the cell's damage-sensing system."

"So if we could produce the enzyme telomerase," Duncan said, "we could keep our telomeres active, protect our cells as they reproduce, and be immortal."

"It's not that simple," Garlin said. "Researchers have actually done experiments, trying to make immortal cells. They introduced oncogenes from simian virus 40 into cultured cells to activate telomerase. Many of the cells died, but some survived and continued to divide with active telomerase, which stabilized their telomeres."

"Why the difference?" Duncan asked.

"There were abnormal chromosomes in the cells that survived. The problem with the research so far," Garlin continued, "is that, as we told you earlier, the only cells we've discovered in humans that have active telomerase are cancer cells. In actuality, most of the medical research in this area so far hasn't been focused on immortality but on developing inhibitors to block the telomerase in cancer cells so they'll die.

"Some researchers at the University of Colorado have succeeded in cloning the gene that activates telomerase in human cells. This has led to two hopes—one that we can develop targeted inhibitors that will attack telomerase in cancer while not destroying healthy cells and secondly that we might activate telomerase in healthy cells to slow down aging andrcell degeneration.

"We think that telomerase activation may be a necessary step for all tumors. The reason for this is that most cancer cells are immortal. Cancer cells, unlike normal cells, can divide indefinitely in tissue culture if given adequate nutrients. Normal cells have a limit of fifty plus or minus ten divisions, the Hayflick limit, before they grow old in culture

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and stop dividing. The ability of cancer cells to keep dividing is believed to arise from the activation of telomerase. Therefore if telomerase is inhibited then the telomeres in cancer cells will shorten and will act as a brake on the cancer cell growth."

"And my telomerase?" Duncan asked.

"It's active."

"Do I have cancer?"

"No." Garlin stood. "You're immortal as far as we can tell. Not only that, but you can replace damaged cells rapidly, as evidenced by your recovery from your gunshot wound."

"How did this happen?"

"The Grail did something to you," Garlin said. "We know the end result—your cells actively produce telomerase—but we don't know how the Grail did this." He turned for the door. "But we will discover it."

QIAN-LING

Artad strode through the main cavern of Qian-Ling, noting the various containers, followed by a half dozen of his kind. The shield generator, a spinning cylinder forty feet long, produced a low hum that pervaded the entire enclosure. He stopped in front of one of the containers right next to the large shield generator and placed his six-fingered hand on a panel. One side slid up, revealing a smaller version of the generator, about ten feet long, resting in a black metal cradle with wheels.

He turned and gestured to his followers. An Airlia got on either side of the generator and moved it out of the container. They followed Artad with it as he continued through the cavern. He paused in front of an intricately designed replica of a dragon—ten meters long, half that wide, with a long arced neck ending at a serpent's face with dark red eyes. Short

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wings extended from each side. The metal skin glittered, as bright as the day thousands of years ago that Artad had captured it from Aspasia's Shadow's forces. It was known in Chinese lore as Chi Yu, the dragon beast from the south.

A ramp, just below the tail, was open, revealing the interior and the pilot's seat. Artad turned to the Airlia behind him and quickly issued orders in their singsong language. Then Airlia and the two pushing the generator went up the ramp. They secured the generator inside and settled down into the seats. The ramp slowly rose and closed.

Using the same drive as the bouncers, Chi Yu rose into the air and turned toward a tunnel that led to the outside world. It disappeared into the tunnel as Artad returned to the room containing the guardian. He turned off the shield wall briefly to allow the flying dragon to depart, then reactivated the wall. He then went over to the guardian and reestablished contact in order to plan the next stages of the war.

IRAN-TURKEY BORDER

Only seventeen miles away. General Kashir could clearly see Mount Ararat directly ahead from his position standing in the top hatch of his armored vehicle. Seventeen miles away and across the border, which was just a quarter mile in front of him. Kashir's vehicles were on the crest of a small rise, the rest of his column hidden behind him. He could see the border post where a handful of Turkish soldiers were on duty. He had no doubts that he could overrun the post quickly. The issue was what would happen in the seventeen miles on the way to Ararat and then on the slopes of the mountain itself.

He knew that his country was gearing up for war, although the enemy had yet to be determined. There was talk of renewing conflict with Iraq. Others said there would be

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jihad against Israel, where all the Muslim countries would set aside their differences and destroy the rogue state once and for all. Kashir thought the first was more likely than the second. His mobilization of a mechanized regiment was lost in all the activity and he knew he would not be missed for a while in his own country. The Turks were a different matter.

Still, he knew he had no choice. He must go to Ararat and do as ordered. He told his driver to move forward while waving his arm to the troops behind, indicating they should follow. Two dozen tanks and twice as many armored personnel carriers lurched forward.

The guards saw the convoy coming and stood uncertainly in the road behind their thin wooden pole. One of them, an officer, stepped up just behind the pole and put his hand up, indicating for Kashir to stop. The general responded with a burst from his fifty-caliber machine gun.

The front of his APC crashed through the barrier. Other vehicles were firing, killing the guards as they tried to run away. Kashir had his driver pull off to the side to let the tanks take the lead.

He put the binoculars to his eyes and looked toward the mountain. So close, yet he knew so much could happen in the next seventeen miles. He keyed his radio.

"Faster!" he ordered.

NEVADA DESERT

Mike Turcotte climbed up the side of the bouncer and slid inside. Quinn, Mualama, Kincaid, and Yakov watched him enter. Turcotte could smell the fear coming off them, no matter how much they tried to control it. They all knew they had been targeted for death and just barely escaped. He'd learned early in his military career that fear was a part of combat and could not be dismissed.

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"What happened to Che Lu?" he asked, noting the blood splattered on Quinn's uniform.

"She was killed." Quinn's hollow voice indicated his shock.

"I know that," Turcotte said. "I just buried her. How did she die?"

"Ricochet off the bouncer. Killed her instantly."

Turcotte sat down on the floor of the bouncer feeling the little energy he'd gained drain from him. His earlier suspicious thoughts about the old Chinese professor and her timing of the opening of Qian-Ling had faded away as he dug into the sand with his bare hands. He remembered her concern for him when he had searched for the Mission.

He looked at each of the four closely. Quinn was in the pilot's seat, a laptop extended across him, screen glowing, but his eyes were dull. Yakov, the large Russian, was standing, his presence filling the interior, the top of the bouncer just inches above his head. Kincaid had his own laptop clutched in his hands.

And Mualama—Turcotte frowned as he looked at the African archaeologist. His initial impression of fear and anxiety from those inside didn't extend to Mualama, who appeared quite unconcerned about recent events. A metal briefcase was at his feet and Turcotte assumed that it held Burton's manuscript.